Investigations of the nucleophilic displacement at the tetrahedral phosphorus - kinetic effects of the nucleophile for a given stereochemistry

OO4&4020/86 S5.00 + .W Pergamon JournalsLId.

Te-trohcdronVol. 42. No. 20, pp. S591 lo 5600, 1986 Rioted inGreat Brimn.

INVESTIGATIONS OF THE NUCLEOPHILIC DISPLACEMENT AT THE TETRAHEDRAL PHOSPHORUS - KINETIC EFFECTS OF THE NUCLEOPHILE FOR A GIVEN STEREOCHE!41STRY.1

ROBERT J.P CORRIIJ, GERARD LECLERCQ.

F. LANNEAU and DOMINIQUE

Institut de Chlmie Fine. Unit6 Associee au CNRS no 1097 Universit& des Sciences et Techniques du Languedoc 34060 MONTPELLIER Cedex, FRANCE.

(Received in France 23 July 1986)

Abstract - R ki?-&tic study of aZcohoZysis and antinotysis of Z-chlom-Z-oxo-1,3, P-dioxaphospholane, 1, shws a mte Zeus ZZing effect of the nucteophiti, where the stereochemistry is retelttion at phosphors. &I the other hand, the substitutions with inversion of the 2-chtorc-2-oxo-1,3, P-diozaphoephorinane & or the dizth~tchlorophosphate, J, sha, a marked infZuence of the nucleophtle upon the reactivity. Furthennore~ tFa large mte increase which has been observed for the hydroZysi8 oC the five-nre.nbered ring phosphorus esters compared to phosp&es (an oxygen atways displaces an ozygenl is not reproduced uben the Zeavirz group is different of the nucZ.eophiZe. !4e suggest thct the mechanistic implications, established in the ccse of phosphate esters hydroZySi8 crmnot be directly extended tc the generaZ case of s,+?(P). The mechcnism of nucZeophiZic substitution of P(4) species is better interpreted in zzems of IIOYO-Lb?.!,” interactions between the nucZeophiZe end the substrate, a process nw weZZ established in siticon chevtistrJ.

INTRODUCTION The mechanism of SN2(P) displacement of the P-X bond (X = halogen, OR, SR...) of

tetra-

coordinated species is commonly accepted to proceed through the initial formation of the P(5) 2-4 intermediate of trigonal bipyramidal (tbp) geometry. with apical entry of the nucleophile. The direct displacement of the leaving group ("ln-line" attack) gives inversion at phosphorus. Retention at P is explained by the initial formation of a tbp structure with the attacking nucleophile in apical position and the leaving group in equatorial position ("adjacent" attack). Then, ligand reorganization

(via pseudorotation or other) allows the apical departure of the leaving

group with retention. The key finding of these interpretations is the initial formation of the more stable tbp structure in terms of the relative apicophilicity of the different substituents r (Scheme l).' X Y

,+JX~ Y’

A

*o

*_b,b’ .Y

1 ,o’-’ 2L X-P' .NU

h

ti”

lx’Scheme

1

* ..... ,’ NuiP%

I-y’-’ A,

/’

‘P Nu' -0

,"w.",00" 5591

.111*110*

R. J. P. CORRIU er al.

A completely reochemistry function

of

species.

Front-side

sive

the

studies

factors

approach

upon

electronic

in

all

the

tionship

of

already

depends

on

and

tives’.

A further

rate

increase(l0’)

one

is

only In

nucleophile based

upon

cement ring

of

by Hall

for

observed

present the

the P-Cl

series

Inch’.

group

solvolysis

of

$2(P)

bonds

different

with

the

of

the

factors

have

way to at

to bc -Ab

inversion

displacement

ratio-

a

silicon.

.

structure

-

have

reactivity

ring

to

compare

nucleophiles

in

upon compound

more

closely

case of

the

Si

rela-

oxa

points

out

and P deriva-

(this)

reactivity.

silacyThe large

relative

to

the

acyclic

group.

changing

we have

This

of of

the 10

leaving

checked,

and phosphorrates.

substrate.

substitution

an oxygen

been

the

displacement

species

replaces

In order

tes.

endocyclic

involved

five-membered

reactions

phosphates

chlorophospha

ii)

intermediate.

the Walden

of

chief

group.

electronic

comparable

studies

and structure

the the

nucleophile

group. of

not

to

of nucleophilic

of

importance

paper,

P are

two Exten-

emphasize

and consistent

nucleophilic

the

groups for a given stereochemistry at phosphorus. 15 we have observed that the stereochemistry Wadsworth

leaving

an oxygen

leaving

Si.

the

of

a simple

of

corresponds

stereochemistries

hydrolysis

and acyclic

tvo work

showed

treatment

facts

to

leaving

ste-

a direct

inversion.

pentacoordinated

offered

was made concerning

the

the

orbital

between

us

the

the

is

and leaving

and

the

the

when

and

the

present

nucleophile,

emphasized

formed

explain

gives

allooed of

data

to

inversion,

(180’)

lability

initially

experimental

nucleophiles

comparison

cloalcanes,which

the

attack

kinetic

of Salem’s

in

the

between

the

silicon

and/or

organosilanes

i)

a new interpretation

invoked

of

of

silicon

of

stereochemical

reported

analogies

geometry

of

Back-side

Moreover.

an extension

incoming

nature

at

at

retention

terms of

substitution

basis,

purpose

in

retention.

nucleophile.

the

mechanisms

the

strong

the

using

between

As also

the

stereochemistry

On this

The main

gives

nucleophilic

kinetic

Obviously,

HOMO-LUMOinteractions

determining

performed.’

nalize

nucleophfle

the (90.)

the

calculations

been

of

the

character

essential

interpretation has been 6 The stereochemistry,

considered

reactions.

attack

governing

initio

different

of St,2 (Si)

the

vith

the

studied

the

nature

of

both

Uestheimer’s

data,

nucleophllic

five-membered

ring,

the

displa-

six-membered

11

RESULTS Kinetics ------__ Organochlorophosphates philic

substitutions

phorus

esters

of

which

give

have

2-0x0-1.3.2

dioxaphosphorinane Water, hsve

or ring

cleavage

the

hydrolysis

than of

the

first

phosphorus In all

phile.

The rate

the

of 2, one salt

to

experimental P-Cl

bond rate

values

than

phosphates

quantitative, attack

at

avoid ring

have

secondary

been

the

adjacent

section)

the

the

carbon

The nucleo-

reaction of phos12 atom. Kinetic I-chloro-

2. used

ester.

constant

as nucleophiles. like

The only

(TEPP). rate

alcohols. to

dioxaphospholane.2,

reactions,

phosphorus

vlth

compared

Z-chloro-2-oxo-1,3,2

:

tetraethylpyrophosphate

(see

the

the

of

and diethylamine

vith

constant

are

and O,O-diethylchlorophosphate,

five-membered gave

reactive

amines

products

-2.

in order

which

cases,

much more vith

on 3 models

phenol

chosen of

the

performed

ethanol,

been

bonds

also

experiments

ditions

been

are

P-Cl

formation particular

Since the value

second

corresponds

Experimental of

con-

pyrophosphate. case

concerned

step

Is

to

the

faster formation

cleavage.

law

is

are

reported

first

order

in chlorophosphate

in Table

1.

and first

order

in nucleo-

Nuclcophilic

1 : second

Table

order

fate

displacement

constants

for

at the tetrahedral

e

\,dJ

o’ 1\CI

N204

0.01

ELal

0.11

PhOH

0.60

LC2NH

0.21 0.55

1 10

PhOH

0.29

I

IO-’

EC2NH

0.18

I

10-2

0.15

x

lo-‘

0.12

x

10-5

0.16

I

IO -1

o.iE

x

lo-’

*

ELmI mm E12W

solvent

In are

highly

It

= 104).

are

the

case

of

dependent Such

neasured

: CHjCN

six-membered

upon

the

various

ring

nature

is not

a difference

for

of

compound, the

2,

observed

in

the

thanol

or

of

derivative. are

strained

much more ,‘.

Very

_2,

the

k-values

reactive close

than rate

alcohols

constants

nucleophiles.

displacements

phosphorochloridates

have

Wadsworth

phosphorus

case

Amines

Table 2 : Stereochemical data of 4 with

Nucleophilic

inversion.14

and acyclic

nucleophile.

Ster.3xhernistry ________-_____

at

in CH2C12).

-6

E LO”

n2o

l

0-C

0.20

K2O

.O ‘P / 0 ‘Cl

c

(at

““H

Reactant

0

chlorophosphates

of

solvolysis

5593

phosphorus

in

amines

the

been

shovn

reported

the

acyclic

nucleophiles

to give

also

coupling

with

of

inversion

reaction

of

me-

Z-chloro-Z-oxo-S-

chloromethyl-S-methyl-1,3,2,dioxaphosphorina15 ne. Ke have reinvestigated that stereochemis31 try using P NMR under our kinetic experimental

conditions

is

predoninant

the

(Table

2).

inversion

The essential at

feature

phosphorus,

whatever

nucleophile.

Sucleophilic xmbered ‘known

ring to

substitutions

of

thio-phosphorochloridates

proceed

The

stereochemical

the

compounds

is

with

retention

s?Jdies reported

have in

fiveare

at been

scheme

phosphorus. extended 2.

For

16 to

phosphorochloridates.

comparison,

we have

also.

The synthetic prepared

the

thio

approach derivative.

to

R.

5594

l(OlPcl) _

J. P. CORIW et

al.

solwnl

3

NO b 2’1. lb’!.

Scheme 2

Treatment of t,3-butanedlol(maso) with PC13 gives the Z-chloro-4.5-dimethyl-1,3,2-diouphospholane (92 X trans). The oxidation Is stereoselective. The same predominant Isomer Is directly formed by coupling reaction of of pyrldlne. If

t,3-butanedlol(meso) with (0)PC13, In the presence of

a large excess

only 2 equivalents of pyrldlne are introduced, the mixture contains the -cls major

lsooe:.17 The assignments as to -cls and trans configurations of the phosphorochlorldate 5 have been 18 'H NMR chemical shifts data. Protons In 1,3 -cis position relative to P = 0 are shifted downfield, vlth also a different coupling constant (Table 3).

made on the basis of

Table

1

: “P

and

’ H N:HR data of I-substituted-

i-cx?4,5-dImethyl-1,3,2

dioraphospho1ane.J.

.. The stereochemistries of nucleophlllc substitutions have been checked by means of “P

NMR

(Tabie 4). In the case of

dlethylamlno coumpound, double resonance 'H NMR technique confirms our assign. 31 P chemical shift at higher mentsof the configurations. We note that the trans Isomers present a 16 field than the cis isomers. The same variation 1s observed In the case of the thlo compound. Based upon our assignments of configuration, the main result Is a change of stereochemistrs, vhen we compare the sFx-membered ring compound 5 (predominant Inversion) and the strained five-nrbered

chlorophosphorus ester.2,

(retention).

5595

Nucleophilic displacement at the tetrahedral phosphorus DISC’.‘SSION Kinetic

results

1, and acyclic

pound,

emphasize

the difference

chlorophosphate,

Table

3 (Table

in reactivity 5)

between five-membered

ring

com-

: Figure

5

1

&tOH PhOH

J

solvcnc

CHjCN

The ratio EtOH (105), influence

of

as a function correspond

exemplified.

case

a ratio, of

of

kc5/kac

hydrolysis

of

That means the Westheimer’s

leaving

rate

constants

of

the

reactivity, that

of

For instance.

that

high fall

In the case

EtOh, a large

for

in the case

down to 7.5.

1, in which the rate

(P) reactant. the rate

of

constants

the Et2NH, close

kc5/kac of

kc5kac

of

The

change of reactivity

constants

the hydrolysis

3.4 x 102, much Lower than the ratio phosphate

significantly

which the ratio

in fig.

vhereas

the ratio

group.

is

for

illustrated

the geometry

the leaving

concepts

the

is

is very depen-

chloro

compounds

106-1Og observed

in the

esters.

the Large kinetic

effect

is not confirmed

which has been essential

in the case

of different

in the elaboration

nuclcophiles

of

and different

group. As a matter

extension

of

we must note

Heanvhile,

order

of diethylamine,

is even better

to a similar

upon the nature

gives

the second

to the reaction

the nucleophile

are reported Ln k values dent

between

compared

of

these

were established

fact

,

the

present

results

to the generality

in the case

(an oxygen displaces membered ring

of

concepts

of

an oxygen).

the hydrolysis What we note,

compounds is no more a rude

reasses

the question

of nucleophilic

implying

of P-O bonds, now. is

, as far

that

as this

6 (ref.

the large

of the

rate

These

intermediates

increase

of five-

s-jmmetry disappears. the same conclusions

been already 10)

the validity at phosphorus.

syazaetrical

Interestingly, Table

of

displacements

reached

of kinetic

and stereochemical

hydrolysis

and methanolysis

membered ring

of retention,

expected bonds.

studies of five

of and six-

oxasilacycloalcanes.

dominant stereochemistry stead

have

from the comparison

The pre-

is inversion

in-

which is the normally

pathway for

the cleavage

The five-membered

an enhanced reactivity.

of Si-0

ring compound shows Such a rate

increase

is not observed

when the incoming atom of

the nucleophile

is not an oxygen (i.e.

bon nucleophilesl. rates

with five

Lacycloalcanes,

These react

and six-membered whatever

car-

at similar ring oxasi-

the stereochemistry.

R. J. P. CORRIUet al.

5596 The particular of

behaviour

cleophile

and

ge”,

to

fact,

this

smetry

the

reaction becveen

In

the

osasilacyclopentane

(Table

corresponds In

of

of

chiasilacyclopentane

large

rate

takes

place

leaving

of is

surrounded

leaving

have

to

be

The pencacoordinated

increase with

hydrolysis

atom

oxygen

increased

group

The phosphorus

in

HO’

p

0

OH

u

This

the

geometry

In

do not of

the

t

&

OH

change

with

at

(Table comes

1).

For

That

Su at

the at

the 1oe.

that

the

relative

nucleophile. 180’

2 x

opposite

vhich

of

with

the

leaving hand,

to

leaving

(0.1

0, C

rate

RO..l “p-

Fig.2

0

leaving

group,

group) in

group)

the

reactions

the

race

(4

is

in

is

is

three

(attack

at

go’),

attack,

b)

equatorial

evident electronic

for

could

c)

the

character

geometries attack,

a”

O-P

of

I

tl sibilities, persutational

this which

monent. are

of

isomerisations.

OH

there

is

similar The

energies. important

with

been

of

the

tbp

for

the

pyramidal

in

Ue observe

opposite,

account

mutual

setting

the

a square

It

geometry,

the

in

be-

to

the attack of

attack

the

con-

case

of

Therefore,

is

the

conceivable the

apical

case

that,

stability

electronic

is inter-

positions.

a large

the

experimental geometry.

of_3

Such

in

in-

nucleophile

nature

2).

case

to

(apical

silicon.

apply.

upon

groups

the

the

reached

mem-

the

(adjacent

upon

at

could of

in

related

on Nu (Fig

pathvay.

Nu. At

of

inversion

substitutions

dependent

hand,

strongly

already

intermediate

five

constants

correspond

retention

independent

rate

: a)

facts

in-

retention

of

(Scheme

4)2’

betveen

the

apical

@

'Nu

no definite

other

nature

is

dependent

have

the

and ethanolysis

vith

inversion

a priori

formation

the

of

< (-y,o_ At

quite

highly

actions

the

60 \

rate

vould

reactivity

proceeding

strongly

particularly upon

aminolysis

same explanations

lnrrrrlon (‘no’) This

for

nucleophilic

RO 5

depending

with

proceeding

rate

the

On the

change

the

reactions

NU

crease

P

of

order

stereochemistry

constants

clusions Cl

0/

substitution

The second

< k < 0.7).

predominant

In the

other

Nucleophilic retention.

considerably

the

a given

On the the

3).

3

observed.

the

constants

ratio

for

are

proceeds

substitution. to

the

evidenced. (Schema

!

the nucleophile

for

rate

-

of

90’

the

means

steraocheraistry

of

2,

example,

%*NH’kE tokl

two cases always

nature

phosphorus,

involved. and

(Retention)

I,

the

are oxygen

activation

-

c O_PIOH

OH

work,

diethylchlorophosphate,

version

of

present

chlorophosphate

importance

and recently

for

osy-

CH30

Scheme

ring

the

species

by Westheimer,

= 33).

another

intermediate.

entering

(Inversion)

bered

tbp

nu-

(tc6/tcj

emphasizes

the

the

oxygrn

displaces

oxygenated

cases,

prosper

3

in

by a”

cons:rai”t

oxygen

nucleophile only

and mechanolysis

group

angular

to

configuration.

as proposed

3 ‘p--3 HO’,

-

‘0

1

0

leaving

when a”

In such

present

by hydrolysis

thio due

esters,

oxygens.

positions,

CH

of

incoming

phosphorus

always

out

the

observed

inversion

of

apical

of

only

and the

/OC”J \\

pointed

reactivity

is

by five

intermediate 0

is

The displacement

a reasonable

the

case

6).

Scheme argument

Moreover point

allowing

the is

that

three in

to

G decide

structures these

three

can

also

three

rearrange

configurations,

the

posby tuo

Nuclcophilic

exchanging

ligands

incoming

orthogonal

nucleophiles.

Initial pect

stay

formation

each if

In fact, of

the

of

other,

which

we considered,

intermediate

=n extra-scabilisation

the

with

apical

O-atoms

implies

a “minimum”

according attack

in diaxial or

to of

alcohol

dered

.>I3

Figure

when the

l_ reacts

ex-

is

with

oxygenated

or

be a more

water rhe chlo-

all

the

not,

the

probable

certainly ___ _ _ - -_ through the formation ramid (attack 5 on a face).

3

the

experimentally,

similarly

could

the

also

nucleophile

Since

(Fig.3).

to

proposals, we would

th,e nucleophile,

entry

due

effect

Westheimer’s

nucleophiles,

torial

a”

A.

the

positions,

rophosphate _;;I

5597

displacement at the tetrahedral phosphorus

of

consiequa-

process, a square-py-

coscLUsIoX The experimental haps

any

case

other

since

the

large

ced

when

reaction

it

behaves

rate the

cas*

in

leaving

the

of nucleophilic On the

and

leaving

“in

line”

phile

and

opposite, of

it

the

the in

orthogonal

substitutions

is

of

group

adjacent exchanging organosilicon

:

the

process

esters

considered

nucleophilic

and per-

as a special

displacement.

For

derivatives

cannot

nucleophile,

both

in P and Si

chemistry.

directly

extend

the

Westheimer’s

five-membered

ring

relationship

rhe

be

instance,

reprodu-

concepts,

esta-

to

general

phosphates

of at

between

stereochemical

corresponds

influence (attack

phosphate be

the

species.

upon

inversion

of

can

ring

structure-reactivity

dependent

giving

case

strained

P(4)

strained

five-membered

the to

of

an oxygen

general

of

of

at

the

hydrolysis

for

difficult

hydrolysis

highly

(180’)

the

different

hand,

the

displaces

observed

substitutions

leaving the

is

the

other

groups attack

is

appears

of

that

from

which group

case

show

an oxygen

differently

increase

Therefore, blished

facts in which

the

90”

to

behaviour

large

is

retention),

ligands.

between

essential we note

The same results were previously 22 dompounds . They emphasize the analogy

nucleophiles.

phosphorus.

interactions

nucleophile

giving

incoming at

The

the

nucleo-

(Ak = 104).

At the

a levelling

effect

noted between

for

nucleophiiic the

two series.

EXPERI?fENTAL 1 Reactions were carried out In Schlenk tubes under dry N2 R NMR spectra were recorded on Varian EM 360 or M 390 instruments vith TMS as internal reference. 31~ NMR spectra were seasured at 32.37 MHZ on a Fourier Transform Brucker Up 80. Positive chemical shifts are downfield relative to external 85 X A3PO,, diluted in D20 (lock signal). Rtactants ----____Some compounds are prepared according to literature, Z-chloro-2-oxo-1,3,24ioxaphospholane, 2. 21r 2-chloro-2-oxo-1,3,2_dioxaphosphosphorinane, 2, 23 diethylchlorophosphate,3,24, 2-chloro5-chloromethyl-5-methyl-2-oxo-l,3,2-diox hosphorinane, 4, 15. They present the structural features in 3 Pp NtlR (CH2C12). 1, 6p + 22.2 ppm ; 2, 6p - 2.7 FPm ; 6p - 3.16 ppm. 6P - 3.10 ppn ; 5, 31 2-chloro-~,5-diaethvl-2-oxo-1,3.2-dioxauhospholane,

.5

Addition of 2,3 butane dial (meso) to trichlorophosphine in dichloromethane Lucas, 25 leads predominantly to trans 2-chloro-4,5-dimethyl-1,3,2_dioxaphospholane. cicn in benzene affords the title product, 2. bp(O.35)87’C, 6H fCDC13) 1.46 ppm (d, 6H) 4.93 ppm (m, 2H). 4.86 ppm t3JP_H 12.9 Hz, Sp (CH2C1,) - 19.4 ppm MZISS spectrum : m/e H+ 170 Found : C, 28.18 ; H, 4.64 ; P. Cl, 2O.62-C&H803PCl Required : C. 28.15 ; H, 4.69 ; P, 18.18 ; Cl, 20. 82 X. The same product is obtained by dropwisc addition co a solution of butane-2,3-dial meso (0.015 mole) in lh. The ‘n filtration of the pyr id inium salt and evaporation of 2. 5% (C3C13) 4 .86 ppm 75 x, 5.03 ppm 25 X. O’C for

Prtdomlnant cis 1 is obtained by dropping and pyridine3.0314 mole) in THF (5 ml) (:3 ~1) and then usual vork-up. 6Ht~~Cl3) TO ?. 6p (CH2C1,) - 19.A ppm

of

trichlorophosphine pyridlne (15

lxcea.q excess

pyr id ine

in

at 0-C a solution of butane-2,3-dial to a solution of trichlorophosphate A.8 ppm (3JP_H - 9.3 Hz) 30 X-S.03

ml) VSCUO

accordin? to Then.

oxida-

-15 %). 18.15 ;

(0.015 with leads

mole) at stirring

to

trans

meso (0.0157 mole) (0.0157 mole) in TRF ppm (3JP_H - 12.9 HZ)

R. J. P. CORRIUet al.

5598

2-~h~oro-~,5-dFmeth~l-2-thio-l,3,2-dioxaphospholane

a,f;?cr3) a,(cu2c12)

tfanS cis

: a.90

ppm Cm, 2s)

: 77.68 ppm, trans

l.kZ

!XX

&and

5y.(~x13f cis 4.90 ppm cm. 2s) 1.46 ppm cd, 68) ppm (d,

were prepared

according

to Lovez3.

611)

: 76.02 ppn

Prozucts ________ The general procedure is described. A solution of nucleophile (0.05 mole) and triethylamine (0.05 mole) in dichtoromethane (Sn!) is dropped to a solution of appropriate chlorophosphate (0.05 mole) in dichloromethane is removed. Benzene (10 ml) is added to the (10 ml). After stirring for 2 h, the solvent resiCue in vacua. The salt is filtered off and benzene is removed.

Subs:itutions

__________________ NuI!

=

of

1

XeOH 68 (CDCl3)

3.9 ppm (d,

Xi,

3J~H3p = 14 HZ)

4.52 ppa (m, Qi). bp (CH2CQ) = 18.1 ppm. “u:1 I EtOH 6” (CDCl3) 1.37 ppm (t, 3H), 4.50

ppm (m, 6H),

6p (CH2C12) - 17.1 ppm

sue - PhOH 6g (CDCl3) 4.3 ppm (m, 4H1, 7.23 ppm (m, SH), 6p (CH2C12) - 11.5 ppm SUL-= Et2h’H 6B (CDCl3) 1.16 ppm (t, 6x1, 3.10 ppm (m, 6H), 4.33 ppm (m, 4Hf 6p (CH2C12) = 26.27 (t,

In the case of hydrolysis of J, two equivalents of triethylamine were used. 9K) 3.0 ppm (q. 6H), A.1 ppm (d, 4H, 3Jp_~ - 10 Hz) 6p (CH3CN) - 16.6 ppm. of

Substitutions -------__------__~

ppm.

dK(D20)l.l

ppm

2

SuH - PhOH 6”. (CDc13) 1.80 ppm (m, 2H). 4.02 ppm (m, &II), 7.32 ppm (s, SH) 6p (CH2’212) - -13.5 (CH2C12) su’r! = Et2NH - +686.8(CLC13) 1.13 ppm (t, 6W, 1.90 ppm Cm, 2H), 3.19 ppm (m, 48) * 4.45 ppm (m, 4W, ppe KuP * Et08 A large excess of titative yield. 65 fCX13) 1.4 ppr- (c, 30,

ethanol 2.0

(10 equivalents)

ppm (m, 2gf,

4.3

is necessary

ppm (a,

6H),

to obtain

bp (CH,Cf2)

the product

PPm 6P

in quan-

- - 7.3 ppm.

Su5s:itutions of 3 ________________ 6H
NuY * ?hOB

ScE - Et2XH 6” (CDC13) 1.10 ppm (t.

6H1, 4.2

ppm (m, 4H),

6H1, t .30 ppm (t,

7.37 ppa (m. 5H).

6H),

6P(CK2C12C12) = -6.5ppm

3.07 ppm (m, 4H),

3.97 ppm (m, W,

c, KE,C12) 10.03 ppn Ku:-:* EtOH - A large

excess

of ethanol

is

necessary

5.16 ppa Cm, 6111, 6, (CH Cl ) - 1.08 ppm NUE - H,O - Tetraethylpyrop 2 f, osphate (TEPP) is

diethylphosphoric 6h (CDC13) 1.60

acid.

ppn

(t,

12H).

6.26

(10

obtained

ppm (m, 8H),

eq.).

instead

6P(CH3CN) = -

bH (CDCl3) 1.43 ppm (t.

of the triethylammonium

9@,

salt

of

13.54 ppm

Prezrration of diethylphosehoric acid _---_____---_-_-_--- --- _____-___ 1 (0.018 mole) is dissolved in hot vater (15 ml). Extraction vith chloroform (4 x 2Om.l) gives diethylphosphoric acid (0.011 mole). 6” eDC13) 1.36 ppm ct. 6H), 4.13 ppm (Is, 4Hf, 11.7 ppm (s. 1H) 6P (CH2C12) 0 ppm. After addition of excess Et3N 6P (CH2C12) = 1.73 ppm. Preosration of tetraethylgyrophosphate _________---________--_ __ _- ____ A solution of 2 (2.4 moles) in acetoaitrile (1 ml) is added to a solution of diethylphoj)horic acid (2.4 mmoles) and triethylamine (2.4 nxnoles) in acetonitrile (1 ml). Triethylamncniun chloride deposites quickly. After filtration and evaporation of the solvent TBPP is obtainad in quantitative yield. Ste:aoc>emi.stry ______________ The

substitutions

chtzistry is attributed

of i and S follow the same procedure than that forA and 2. Stereoare reported d Tables 2,4. by means of ‘: HhR and/or 31 P NMR. The results

Kinarics ----_.%___ Dichloromethane sive

disrillations

Methanol

and ethanol

(x

is distilled over P 0 under nitrogen. Acetonitrile is dried by succesover KOH in pel1ets before distillation. P 0 . Amines ar8 sefluxed are diseil I2e over magnesium methoxide and magnesium ethoxide. respectively. 3)

over

Kinatics method _--_______-___ AIiquots of the reaction mixture (S ml) are run The rates are measured by acidimetry. at -20°C into dichloromethane (25 ml), and a solution of chlorhydric acid in toluene is added. The amount of chlorhydric acid is calculated to be equal to the initial amount of the amine in the sample. The excess of acid is quickly back titrated with a standard solution of triechylamine in :oluane with neutral red as indicator.

Kinetics measurements ____._____________--. ALL kinetics runs were performed at O’C in ice bath. TVQ procedures were used depenFor a slow reaction the mixture of triethylamine and nueleoding on the rate of the reaction. of chlorophosphate in philr? in dichloromethane (25 ml) is added (at O’C) (t - 0) to a solution dicittorcmethane 125 ml) at O*C. Aliquots (5 ml) are titrated at various intervals. For fast reactions, 2.5 at of each solution are mixed and the same procedure applied. Second order rate eonscsnts were calculated from the equation 2 where a and b are the initial concentrations of phosphoroobloridate and nucleophile and x is the concentration of KC1 at time L. For the hydrolysis of 3, a different equation was necessary (eq.3). eq.2

kg--&-

Log

-

a(b-x) b(a-x) Table

eq.3

7 - Experimental lconeentrations

k2t = -+ rate

orders

in mol.1

Log

a

-c

a(b-x) bo

at 0°C 1

R. J. P. CORRIU et al.

5600 REFERENCES

a prelimfnary report, see R.J.P.Corriu, C.F.Lanneau and D.Leclercq, Tetrahedron Lett. 40 4323 (1983).

1

For

2

3

Ibid -. 5 204. F.H.Westhelmer, _---9 Accounts Chem. Res. 1 70. (1968) b) R.F.Hudson and C.Brova, -1 40 595. (1974). d) P.Gillespie, F.Ramirez, I.Ugi, (1972). c) S.Trippett, Pure Applied -Chem. -* D.Marquarding, e. Chem. Int. Ed. M., l2, 109. (1973). --For a general compilation see : W.E.Mc Even and K.D. Berlin "Organophosphorus Stereochemistry Benchmark Papers in Organic Chemistry", Vol.4, Dowden Hutchinson Ross, Stroudsburgh USA,(l975; and Related Elements". R.Luckenbach : "Dynamic Stereochemistry _of Pentacoordinated Phosphorus -Thieme - Stuttgart (1973).

4

C.R.Hall and T.D. Inch, Tetrahedron, 36, 2059(1980) and references cited therein.

5

R.Holmes : "Pentacoordinated Phosphorus". American Chemical Society; Washington DC, (1980) ACS Monograph No 175-176. R.J.P.Corriu and C.Guerin - J.O?ganometal. Chem. 198, 231 (1980). Nguyen Trong Anh and C.Mf.not - -----9 J. Am. Chem. Sot. 102

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10

R.J.P.Corriu, J.M.Fernander and C.Guerin, ----2 Now. J. Chem.8 279, (1984). See for example : a) J.Kumamoto, J.H.Cox, Jr and F.H.Westheimer, J.&. -Chem. Sot. 78, 4858,(1956)b)H.G.Khorana, G.H.Tewer, H.S.Wright and J.G.Moffatt, ibid, 79, 430, (1957). c) G.Aksnes and K.Bergesen Acta Chem. Stand. 20, 2508, (1966). d) @.C.Ha and F.H.Westheimer, J.&. -Chem. Sot. a3,1102(m) e) I.Dostrovsky and M.Halmann, J. -Chem. Sot. SO?, 516,(1953) M, 1004, (1956). f) M.Halmann, M, 305, (1959). g) R.F.Hudson and L.Keay, ibid, 2463, (1956). 1859, 1865.(1960).

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12 13 14

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C.R.Hall and T.D.Inch, -J. -Chem. -Sot. --I Perkin I -1 4 1104, (1979). K.S.Wadsworth, Jr; S.Larsen and H.L.Rorten 2. 9. 38 256, (1973). W.S.Wadsworth, Ibfd. -Chezn.-) s, 2921, (1973).

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H.Mikolajczyk and #.Witczak, 2. _Chem. _. Sot

17

Perkin I -* 20 2213, (1977). -* a) R.L.Jarvest and G.Lowe, ---J. Chem. Sot. Comm. 364, (1979) b) J.Gagoaire, J.B.Robert, J.Verrier and R.Wolf, Bull. -Sot. Chim. 'r. l2, 3719, (1966).

18

a) D.Z.Denney, G.Y.Chen and D.B.Denney, J.Am. -Chem. Sot. 91, 6838, (1969). b) K.G.Newton and B.S.Campbell, ibid, 96, 7790, (1974). c) P.M.Cullis, R.L.Jarvest, G.Lowe and B.V.L.Porter, J. Chem. Sot. Chen. Comm. 245, (1981). -----

19 20

E.A.Dennis and F.H.Westheimer, --J. Am. Sot. a, 3432, (1966). S.L.Buchwald, D.H.Pliura and J.R.Knowles, J. ---Am. Chem. Sot. 106, 1916, (1984).

21

R.J.P.Corrlu and G.Lanneau, J. Organometal. Chem. 67, 243, (1974).

22

R.J.P.Corriu, B.J.L.Henner, J. Organometal. -Chem. -) 102 R.S.Edmunson, --Chem. and Ind. 1828, (1962).

23 24 25

407, (1975).

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