Reaction of difluorocarbene with small bicyclic molecules

Te-m Vol. 43. No. 4, pp. 653to 662.15’87 Printedin Chat Britain.

REACTION

oo40-4mm t3.oo+.a) 0 1987FugnmonJo& Ltd.

OF DIFLUOROCARBBNE

James B. Jackson,*

WITH SMALL BICYCLIC

MOLBCULESt1’2

Ulf Miaalitr. ?&&land Jones, Jr.+ and A. de Meijere+

Departm&mt of Chemistry.

Princeton

Univereity.

Prinoetop.

NJ 08544

(Received in USA 11 June1986)

- Difluomoarbene

Abstract

the product yidli.

reaote with 1.2.2-trimethylbioyaloU.l.Dlbutane

of two bond aleavage.

Bicyclo[2.l.Olpentane

diene in 08. 0.5% yield. Theoretical

1.1~difhmro-3,3,4-trimethyl-1,

ia even leee reeative.

Bioyolo[3.l.Olhexane

deecriptions

to give

I-pentadiene

yielding

in 3%

l,l-difluorohexa-1,5-

does not reaot with difluorocarbene.

of these reaotions are discussed.

Introduotion Over the last several carbenee

with carbon-carbon

lionSO expe&ental hydrocarbons

years

detafla have Been laoking and a variety

hax been deearibeQ.

difltirocarbene.

previous

work has been

single bonds and for good reason: contairiing operating

for the

and

exotic kinds

reaction of bonding

Reaction of Difluorouarbene Like two

the rea&n

at all activation

are required

with the vxrtous

small rings. of carbenee

almoet doeanY occur! must

with carbon-c&bon

nNormaln C-C bonde dd’not

be preeent.

and even in euoh ceeea yields

even for such voracioue

eleatrophilee

Thue are low.

We -aBrB

ae oarbenea.

Thue CF2 &ebinae

dMuolaarbensreacte*hbiuydObutaneeby

with 1.2;2-trknethylbicy&[l.l.Olbutane

(1) to give l.l-di-

fluolrr3.3,4-trkwthyl-1.4-pentadiene (2) in 3% yield. DEloo~waeg@xwlatedbythemethod of Burton, 5 under which conditions 1 waa apparently converted to vinylaycloproparies eubstantial

mol&ulee

with Bicyalobutane

methylene and dloarbomethorgcarben,&*=

bond deavage.

reacting

of Iha reaction of’ a eingle carbene,

msported on the reaction

to ocour

at the limit6 of reactivity

of tines

Here we deport the details

with a epeotrum of compound6 containing

Little reactsCg4

we have oommuniaated a number of papers on the reactions M in highly strained ringr. 2.3 Wtth one exmp-

aingle bonds contained

amounta of 5 and 6 were ieolated along tiih

2?

Diene 2 wae independently

5 and 4 ae aynthe!efsed

1

by a sequence “iatnareanin

starting

fmm pivniolaatone?”

tarmedtate QT natt*

euea

etrongly

againet

oal b

ioWed.

only

a meobardem invd&g

to euffer

Queetione of makniLm

We”have ran&d

olmvage

to

a twb-etep the

dlbne. 653

are reduaed

b the claxeic

befas~~‘~

tbtfHM_tond&lneee&hm2 reaot&m in which an int&med&te For bath

&erlc

and

eMotnMd

&&Iiranu&

diradical

7 should

2 and 2. 8-e

be favored

over 2.

It Beems inevitable

of the increaeed

thermodynamic

stabtltty

tect 2
besides

but rather a conoerted

Thin notion, theoretical

aa well aa further

investigation

7 haa two poaaible cleavages leading to dienes

intermed~te

that in the traneition

etate for this

second

step in diene formation As we are unable to de-

of 9 over 2 would be felt.

2). it Beema highly probable to us that the reaction fs

one in which the central and one side bond of 1 are aleaved.

details

of a number of poesfble concerted

paths

is revealed

by a

of the reaction at the MNDO level.*

Y ~

r).

l.

\,

1

CF2

o

k

.>h ,$a P .CF2

-4”,

7 We have 30 btoyclobutane .

prevfouely

umbon-hydmgem

imertion

One, (TS “C”) invdvea the intervention butane

(High+

In t+

parallel

transit&m

11.

with

Aside

from

for the react&xx.

etzu&u&m

As the central

electrophilio

with, a mxbene

molecular

the

oriented

so u1 to best overlap.

or LUMO) with a filled 1 orbital

At a Closer approach,

stage.

oarbene

Orbital,

favorably rotatea

that this add&

to a carbon-oarbon

The planea of the carbene

to interact

begins

Ultimately,

bond in bfuyalo-

pioture of the addition of methylene

Unoccupied

early

w&ha&

-bon-carbon

pure 2p orbitah+,’ it comes aa no surprise

or HOMO) of the olefin.

ep2 orbital

defin.

of :CB2

heret

top-aid% attaok and lmda to ~tl.l.ll~~e

pioture, lo reaotion begins

at this

filled

of the

desoription

th-

face figure

(the Lowest

Oocupied N.O.,

down as its orbital

a rmnw of two essentially

2p orbital

eseenttally

we find

pathways,

&oaely th+ beet theoreticat

double bond.” ite empty

e theoreticai

CF2 of the reaction

of eompar$son we witl sumatariae our findings

of an intermediate

is oenstructed

tion resembles

reported

For purposes

2

>(-

and the olefln are the oarbene

with the now somewhat

to the orientation

found

pitchee

dfatorted

in the

I*

product

cy&opropane, The computed outside side

paths

to diene producta

of biuycbbutane,

2p orbital8

ping with o* of one of the bioyolobutane’s The Cl-C4

the aide bond broken.

point of cresting

the activation side apprxmch.

symmetry,

converting

structure

so product A third

barrier.

the energetic

anti-planar

transition

as the a&me

degeneracy

the methylene-bi~y~lobutane

than

distance.

etruoture

opened

farther

in the traneition

and ia now n+y_

1800.

determined

‘nBn [figure

at the

21 involves

a

adinuee

to appe

interaction

stage

as evidenced

is purely

that in the transfAs yet the electrophilic.

and C-H bond pair electrone.

qethylene.

Sipribrly,

where the fragments

(TS more

of the oarbene-C3

as .dtfluoroaarbene

Bond auMn&j and breaktng haa prq&+!+i methyiene

in the top approach

atage of the reaction

by the Bhortening

is also apparent

etate than haa

ogous reaction of the muoh mora reactive

bioyclobutane along

of TSa *A* and vBn to man

the oar,bene% lone-pair

of methylene,

The onset of the nuc@ophilic

eubstantially

18 already

However.

for the addition

lone pair in the

to the cerbene%

addition of :CF2 is similar [figure 1.21. i8 substantially less symmetrical, with the eleetrophilic

“P”) addition

orbital overlap-

again without an intermediate,

regioeeleotivity

Qualitatively, advanced

attack from

Thie TS fs nearly degenerate in energy with “A” but quk!ldy breaka

“feela* no difference between

bicyclobutane

This leads,

side bonds.

to A-like at~ctures

We interpret

thfs path.

by carbane

and the oarbene’e filled hybrid

bond of nAR, situated

TS, ie uniformly more m

arising

“AA”Hlgure 21 methylene apprcacbea the

the mapty Zp orbital Gwnbane LURK0 ovarlapping with the rear of one c4 the

making up the HOAl of biayulobutane,

to 1,4-pentadiene.

tfon

are quite different,

In .tranoition etructure

and Wow the bridgehead.

ha8 tilted aver

the II-C3-Cl

angle has

furt!mr than ih the analare barely distorted

from

Iceacdwofdaaorocutraw: their

stmting

additk#

gecasetriee.

and thue

higher 8utivation energy Table 1.

&ate coxes

[tables 1,21,

fCF9)

ia participating

mdatively late and naturaEy

in ,thta ease 44.X vs.

in a 1em1 exothemnk has a 8Ubat8~&i.tly

17.9 ktilmoi,

,Huats of’zkmuation and Activation Sucrgkm

T.S.

Descriptian

. 1 +

The more stable carbene

the transitian

655

‘CR2 CA)

Figure

4%

Sa

182.5

11.1

2

1 + lm2

tIti

182.6

Il.2

2

1 + %I9

CC)

189.3

17.9

1

1 + lCP2 CD)

25*58

26,7

2

I + %X2 ma

27.26

28.4

2

1 + lCF2 CF>

43.01

44.1

1

10 + %I2

(0)

15J.99

18.4

4

10 + %X2

(HI

159.54

22.0

4

10 + lCH2 (I)

156*76

19,2

4

10 + km2

(3)

161.70

24.8

3

10 + kq


7.98

43.9

4

10 + lCP2 CL>

12.55

47.5

4

10 * lep,

*

19 + lCF2 CM)

ZS - oC%mlpmBe tb ‘R” or “ti 19*70

3

54.7

aA eewnd-order stationary point or %iUtop* , showing 2 negative eigenvaluea of the second derivative matrix. In this cam, when unconstrained, this etructure cchapsea toward etructure type “A”. bThe H-C-H or P-C-P angle bimctor of the carbeue is approximately eclipeing the bond from C to the ihdicated stool, as rhoun by the NePrman projections in the figures. In gene&, this is thd aide bond which ie cleaved. Table 2.

Heats of Formation of Starting Materfals and Products mm0

&gf

hxp. A&f

CH2flAt~

107.4

-m2.013

CP2 ?A11

-65.2

-44.514

~cy~[l~~“OJ~~~~e

64.Y.

51,915

Biayclok?.~.OJpantane

30.2

37.715

I* 4-Peutadiene

24.3

25.3=

~e~~o~l.l.~J~e~~~e

58.3

49 615

-74.3

-L6

-33.6

-42.516

1 t 3-Hexadiene

19.9

20.117

Bicyoloi2.I~llhexane

19.3

15.315

l,l-Difluoro-1,!5-hexadiene

-79.0

-63,716

6.PDifluoxobk?yclo12.1.IJhexane

-71.6

-76. aI6

4-pentadieue 2,2-~u~b~y~o~~

.i.l

Jpentane

6%

J. E. JMZ~ON a rrt.

R R

.. A R

R b

R

R R

R

J. E JACKSONet al.

H

H

1

J

M

659

Reaotion of Difluoroarbene

with Biayclo[2.l.Olpentane

Although neither dicarbomethoxycarbene banda d

Moy&[%.l.Olpentane

in only 0.5% yiedd.

Oeneratioa’

mga?dul

eatabliehed

in 12 led to l,l-difluomhexa-l,B-dbne

(13)

(14) in approximately equal amounts. Authentio synthewe of 21-25 Unfortunataly the preeenoe of 14 oannot be atruoturea.

their

Deapite our beat efforts.

u dgnificant.

reaota with the carbon-carbon

doea. although the cleavage produat is formed

of. difluorocarbene

and e.6~iilwrobioyolo[S.l.Olherne both produote

nor phenylcarbene

dtilucmarben,

(l2j.2

+

:CF2

we were unable to obtain bioyclopentane better ,2

bF 2

12

0

+

I

SF2

,-_

14

thul

It aeeme very

as.79 pure.

diflwcwarbsne

to generate

likely that the meidual 0.3% cyclopentene

reaated rapidly with

It is also poaeible that emall amount8 of

the amall amounts of 14.

cyclopentene am formed from 12 during the reaction. We have compared the calculated with aethylene

rcmotion cd biqklopentane

the more &able bicyolopentane butane

[ampam

reaotionne of difkuomrbene itself [figure8 3.41.

with

aalouhtionm

the

for

Top approach by difluorocarbene to

(TS “la”) is even more difficult than ie top approauh to biuyoloOur calaulationa at the MNDO level give an aotivation energy

flgureer 1.31.

of

nearly 55 kcal/mol oompared to 24 koallmd for the analogous attack of methylene on bioyolopentane (TS ‘J”,

figure S) and 43 koallmol for top approaoh of difluomcarbene

to bicyolobutane [table 11.

Cl-C5

appmaoh with the R-C-R angle k&e&d by the Par bath DMlylene and dlihnwarbene ti bond (TS VP, “Kn, f@um 4) ia batter by S-4 kcallmd than the andoga~e Apple& with the

Cl-C2

bond on the carben& biee&x

eecond,

nucla@ilic

[TS’a “Ii”. “L”, ngulw 4. table 11.

etage of the reaction to prooeed aa the filled carbene hybrid orbital overlapa

with the empty a* orbital of the Cl-C5 the dlfiuomoubene figure

llliaiunmwearyforthe

ma&ion.

bond, and ie in aouord with the formation of heudiene

It doee suggest

that

formation of ally1 cyclopropanee

4) might be achievable under come circumatanoes

(TS

in “L”,

should a way be found to diefavor the

cleavage to hexadienee . Many of the featurea bioyalopentene

reactbn.

apparent

In the reaoUon with bicyolobutane

In the oxaputed

traneitlon &v&me

ie methylene (TS “On) to ite final pea&ion. aa the diflw the pmoeaa. b-me

also appear

“K” difluorocarbem ne trandtbn

in the than

ti alaqr

state M

later in

The Cl-C5 bend hss ~amPemd1oitaRdQhboB.C4-C5.whlohrrpsventully Meanwhile. the oarbene carbon ia flattening towardr ita ulna p&tion

a double bond.

in

the diene produot. In the case d

difluomrbene,

whioh the bioydopentane’s

Cl-H

aearehu

for

tratmitbn

bond lice near the oarbene’r

atruotures

like “1” (figure

biaeutor plane,

invarIably

41, in led to

I. E. J~cr;ro~et ai.

660

carbene

rotation,

bicyclopentane struoture point

giving

conforma~ne

are on the bioector

“E” (C B eymmetry)

ae n&ad above.

like “K” or “L” where

instead.

Thin result

the Cl-C5

in con&tent

for CP2 attack on bioyclobutane

or Cl-C2

bonds

of the

with the observation

in in fact a eecond-order

that

stationary

CPZ+bkzy&ip0ntameaclee,not3trdumdthia

Thueinthelower~

sort oould be found. Reaction of Difluorocarbene Generatbn produote

incorporating

difluorocarbene.

wtih Bioyclo[3.l.Olhexane in bhyclo[S.l.Ufhexane

of difluorocarbene

15 and the

carbene.

+

NMR

eral RIectrIo/Nicolet (6 0.00 ppm).

reached

led to no

the Rmita of reactivity

of

of ‘normal” hydrocarbona.

-

.CF2

15

Dhta.

(15) by the same method’

we have

Compound 15 fits firmly into the category

0 General

Thus

NoMducb

BXPERIMRNTAL

qmcttmm

moorded

spectrometer

m

an IBWBrRker apwWmWrWI4250(2502tH5)aaGat-

GB/NT 300 (SOB MHz) with tetrametttyleiIane

13c-NMR spectra wmW m

at an IBM/~er

MHz cr a GanentI lRectrWNkx4et GE/NT 300 @actmMW form aa internml &andaxd ( 6 77.0 ppm).

aa IntemaI

WI4250 rpe&umW

standard

-ted

at 52.Q

operated at 75.47 MHs with &u&&MaW

lgP-NMR spectra were teuxded

on a GeneW Bleatrlc/Nk&it

GE/NT 300 epectrwneter operated at 282.32 MHz or an IBMlBrItker NR 80 epeotnometer operated at 75.29 MHz with trichloroflnorcm@thane

or hexafluorobeneene

IR epeotra were recorded

88 internal

etandard.

on a Perkin Elmer model 283B spectrometer.

A IIewIett Plxknrd 5992 B GClbIS &lectxm

impact, 70 eV) was umd for mutine maaa spectra.

High remIuticn mesa epectnt were recorded on an ARI-MS 9 @ectmn west Center for bIadaseSpect’rographic Preparative

Analysie.

Lincoln,

impact. 70 eV) IX by the AIld-

Nebraska.

gae chummtographic eeparatlcna were performed on a Varian AWJP gae chmmato-

graph equipped with a W~ll4~ stainlees steel odumn packed with 10% PPAP cn Chrumar& 80-80 meeh Gzohtmn A1 or with a llW/4” cyanide and

on Chrancaor b P-NAW, 45-80 mesh Gxhnun B) with helium M carrier gas.

flow rates are specified

StalWlgHydmcarbone impurity : impWRy:

publl6hed methods.

potassium

were purified

fluoride Procedure.

mmol) of trimethylphosphine

bromide had formed. product6

and relative yielda d

Reaction of 1,2,2-Trimethylbicyolo[l.l.Olbutane As described condition8

total yield separated

for

After

into a sdution

St&&g distilled

the diflwmcarbene aa internal

glansware.

of 2.62 g (10.0 of (bromodi-

qmol of the hydro-

was oonunued W 48-12 h at room temperature

under

adducta wem determined by inteintegration

standard.

(1) with Difluorocarbene

in the general procedure, 0.85 g (8.3 armI) cf 1 wera stirred undar the reac72 h.

of difluorocerbene

kolation adducta

yielded

1.00

g of a very volatile, colorleas liquid. 19 The adducta P-NMR epectroscopy .

was 21.9% by

by preparative VPC Gx~IumnB. odumn temperature:

by lnoreaaing

WW=ttene) and

argon in flame-dried

30 min 8.0-10.0

were added. were flash

gration of the lsF-NMR Bignale with hexafluorobencene

tion

impurity:

After 1 min a white precipitate

and 10 mL of triglyme.

Then all volatile

Abedute

under

(2.09 g, 10.0 mmoll wan injected

Major

(99.7% by ‘H-NMR, major

‘H-NMR, nrw

a ’

and 2.32 g (40.0 mm& of potassium flu&de

at room temperature. vacuum.

by

All carbene reaotione were performed

fluoromethylltrIphenylphcephonium

high

(98.a

lH-NMR.

TrigWe. trlphenylphosp~. cMbe_ as previously described by Jefford -et al.26

Pre-cooled dibromodifluorcmethane

carbon

@S.O% (LB memured by bioyclo[2.l.Olpsntane

1-methyl-1-iso-propenylcyolopropane), and bicydoI~l;O~xane

cydopentene)

WecB obtained by General

Cohnnn tuaperati

for each separation.

l,2,2~lt4cyclo~l.l.OIbutane.

.

W-AW-DBCS ,

etaMesa eteel cckuun packed with 10% A.gNC3/30% benzyl-

retention

4OW. b:

6H1, 1.76 (be, SH). 4.14 (dd. 1H). 4.74 Gnc, lH1. 4.87 ppm (be, 1HJ. 6 -92.0 ppm CAB, 2Pl.

80 mL/min) and odlected

ttmea 88 eolutions in deutericchloroform. ‘H-NMR (250 MHz, CDC13): (2. 3.1%):

I. l,l-Difluoro-3.3,4-trimethyl-1,4-pentadiene

The were

6 1.26 (be,

lsP-NNR (75.29 MHz, CDCL$:

Reactionof m II.

661

2,2-DKluoro-l-methyl-1-(l+nethylay~IIqy~roDene 6 0.28
cDCl$,: (‘5.29 III.

m.

8 -129.1

YHr. cDC13>:

(5.

6.72 (&lU, 1H). 0.86 (dddr lF0,

(6.

6 -138.3

MHs. CDCl$: To a ~@wII&$

diethy

12.3 g (67.1 mlml) d

pyridlnium chbaprr

After 1 h the mixture wae diluted with 160 mL of dry

Thehemich~medeosntedandthereePdualblaokgumrraehedrrith~~

portiona of dry diethyl ether. dietllhtion

The oombined orgakiic layers were filtered through Floriefl.

et etmoepherle

bp. 1OkC (lit.”

1 ‘2-5

A 801-n

preerure

yielded

2.46

Praa-

g (58%) of 2.2.3-trimethyl-3-buten-l-al

oCl138 torr).

1,l-DUl1xn~-3,3,4-t?imethyl-l. furan

d

in 50 mL of dry dichloromethene in one portion et mom

under an ltmaebhbre of argon.

ether.

HHS,

1sF-N18R

in 50 mL of dry dioNommethrns wan added 4.34 g

mad) d aodium e&ate

amol) of 2.2.3~trhaethyl-3-buten-l-ol

temperature

tional

(250 Sm.

2,‘2,2-Trimethyl-3-buten-1-U

ettrrmd ml&s&ml

ma&&ml&

chrmmte and 0.93 g 01.3

Wit.

18P-NMR

ppm CAB, 2F).

Indetmndent Synthesis al 1,1-~~3.2.4-th~l-l,bpentadiene.

(39.8

&mt

2.3%):

6 0.25 (no, 2H). 0.86 (UPC.2H). 0.84 (mo. 2?I), 1.0’ (d, 3H). 1.1’ pp~ (t.

cDC$, :

(250

PPQ CAB. 2F).

tluYm-2.2-DKhrxWl-mthyi-l-W9euW~

(‘5.29

lH-?m.

16.6%):

1.1’ (8. SE). 1.28 pp~ (*. 3H).

4-mntndiene

of 0.48 g (4.52

(2)

mmol) of lithium diieopropylemide in 6.0 mL of dry tettiydro-

wee added dropwiee to e mixture of 0.85 g (4.52 emde) of (diethylphoephiny1Mifluo~ 2’ After 1 h, 0.56 in 2.5 mL d dry tetrahyd~#uran at -78W under an etmmphere at argon.

methane g (4.46

mmol) of 2.2, S-trimethyl-3-buten-l-al

wea added.

The mixture wee stirred

another hour and wan then allowed to warm up to rooa~ temmture brown sdution tmperature adutbn

wan refluxed

perature:

4 ii mdecuhr devee and purUIad by prspaattve lH-NbtR (256 MHz. CDCg):

IH), 4.74 (me, 1H). 4.8’ ppm (be. 1H).

lG eV): ’ m/e = 146 (43). 7’

(45).

146.080’.

67 (19).

Found:

131 (1001,

65 (17).

111 (231,

53 (13).

(2,

110 mg,

17%):

6 1.26 (be. BH), 1.76 (be,

13c-NMR (‘5.4’

yield 1.34

MI&., cDCL$: 6 19.5 (8).

odorless

B. odumn temperature:

91 (21).

89 (10).

85 (13).

83

C6H12F2:

mmol) of 12 were rtirred

for 70

The total yield of difluorooarbene adducts

h to weu

The adduote were separated by preparative VPC (a9umn

IOW, flow: 120 mL/min).

I. 6,6-~t3.1.01hexalm ppm (d,

0.68 g (10.0

liquid.

1 .l% M d&em&ed by lsF-NMR npeotmmopy.

lH-NMR (256 btHz, CDC13):

(14, m. 0.5%). ppm (m, BH).

lsF-N?dR (‘5.29

‘fF F = 156.1 Hz, 1F).

118.0594 + 0.0012.

105 (5’).

Preaire mace. Caloulnted for 2.

(12) with Difluomoarbene

g of a very volatile.

1H). 1.81-2.08

109 (12).

51 (17).

Ae deeoribed In the general prooedure,

-149.3

B. aohxnn tern-

bdmn

146.6805 + 0.0612.

Reaotion of Bio~olo[2.l.Olpent

(mc.

Thin

Thereeidual

37.4 (81, 86.8 (dd. = 19.6 Hz, 2& F = 15.1 Ha). 168.0 (a), 151.1 (a), 155.2 ppm ‘& F = 292.9 Hz, l&,F = 28611 Hz). lsF-NbfR i’5.29 MHz, CDCL$: 6 -82.0 ppm CAB. 2F). bt8 P

W,

(101,

VPC

1,l-Difluor~3.3,4-trðyl-l,4-pentadiene

1’56 (&=CF2), 1625 ani” (C=C).

3H). 4.14 (dd,

(‘0

were flash dietilled et room

The dietillnte wee diluted with 5.0 mL of n-pentane.

SOW. flow: 256/mL/l&n).

IR (neat):

(dd,

Then all volatile products

et -78OC for

pirully the dark

wae weah& wtth 5.0 mL of water, 50 mL 5% hydrwhbrlc addand56mLwetar.

liquid wan dried uv=

27.5

for 12 h.

under reduabd preeeure.

In about 1 h.

Mix. CDC13’:

prealee mnea. -ted

6 125.9 (d.

6 1.51 (mo, lH), 1.72 2& F 156.1 He, lP),

5~ 14. C6H8F2:

‘118.0584.

F-d:

*

II. l,l-Difluorohexa-1.5~diene

(13,

a~. 0.5%).28

Bioyolo~S.l.Olhexane A mixture

of 41.6 g (0.62

mol) of &no-oopper oouple end a orystel of iodine wae stirred

under 250 mL d dry ether under arga~ until the blroan c&r mol) d

oyolopentaw, (dried w

added in cuw portSon.

4 K raswulu ThemixhllWwMr&uxui

Mae)

appeared.

A mixhm

4

38.8 g (0.5’

end 166.5 g (0.62 uml) metbyWe w&de W

tar 6 h. oo&d foa 3 h and m

M

agein f&

15 h.

The mixture was filtered through Cdita and poured into 108 mL of a OCJ&~ -ted NH~C~ eolutlon. ‘The & hver wea mpuated and weal& rtm 3 x 100 mL porthrv d w NH4Cl, 3 x 100 rnL SatumWl NaHCo3. lx~mLm~~~8203udlx100mL~o. AfWd@ngover the advent wan oa!@et,tsly removed by dietllkati~~~thrargh W304* Fmotbnatlon of the reetdue yielded 14 g (30%) of bloyolo[S.l.Olhexane.

a 20-inob

29.30

VlQmx

odumn.

J. E. J~cx.w~ et al.

662

Reaction of Bbmde[3.l.Olh~ne

(15) wlth.Difluomcorbene

Ae deecribed in the generaI procedure, 0.88 g (9.8 qmoI) of bicycloll.l.Olhexane worn for 72 h to yield 1.50 g of a very volatile odorlear liquid. Inepecticn by ‘H- and l@p_

stirred

NMR qmctmoooppy ahowed no difluorooarbene YNDO

puted

calculation8

by the metrioted

further

examined

by

reeulting lcterlxed se-point

by

VfbrationaI

energy

such

t

a aIightly

(RHP) method.

the open-ahelI

struotume

relatively

analyeie.

Ueing

caloulated Olven

the

between barriers

the

adjustments

interaotion

shall gnalnd .etate, maultent

the rtarting

muoh larger

an ZPB dlfferenoer

m

corn--

8truotume

option

worn

lvaBaQIe in the

Muda

the trro amflgumtkxle

Ail etaticnery

pointe wem fuIly char-

vibrational fragment6

uncertaintier

to reproduce

of the MOPAC

Ail etructume trandticn

frequenoies. and transition

by mom than ca. 1 kcallmol

of a method calibrated

eubtle

in&g¢

modified vereion

In ecme oaeee.

3x3 oonfigumtion

in uidttkm to the &wed

(ZPB) diffemncee

> 2.5 koallmol).

coneidered

out by using

from eingle and double HOMOto LUMO excitations.

not ohange the relative tranrltion

carried

2.08) runntng QI a VAX 1111BOminim~~uter.

Hartme-Pock

using

MOPAC program *Nob.

never

rem

(QCF’E 8455, vemkn

paokage

adduota.

Detalle

Com~utntlaul

(absolute

inherent

the propertiea and thermal

correction ltruotureo corrections

In the application of ground-etato

energy

oorreotlons

for did aem to

minima, were

and am not reported. RBPBRBNCBS AND NOTES

Dedicated to Pmfeeeom Jchannee and Hildegard Padelt on the occaelone of their OOth birthdaya. + Permansnt ackhwe: Inetitut fEr O-he Ch&e und Bbchemb. Urdvemitgt Hunburg. Federal Republic of Qermany. 1. Support fa thie rmk by the %&ml S&m F~nde&n through gmnt CHR W-18345 .L wandy aoknorledged. We am also grateful for the award of a fellorrhlp awarded to UM by the Studienatiftung dea deutsohen Volkes. We thank Princeton Univeml~ for the award of the Charlotte mbeth Proctor FeNowrhip to JKJ. 2. Q.-H. Shiue, u. Miwlitz. x.-t. Ding. M. Apcr&ndthterrorkhmmbeen ccmmu&XtecI hr. Jones. Jr. and A. de Meuere. Tetrahedron f&t.. 5399 (1985). 3a. Q. B. Meek and M. Jcmm. Jr.. Tdnhedmn Lett., 3819 (1881); b. N. L. Tet& and Y. Jonee. Jr.. Tetmhe&cn I&., 16l (1964) I o. J. B. Jackmn. Q. B. Mock. N. L. Tetef, 0.-x. 2heng and 111.Janss. Jr Te U. 1453 (1985); d. U. Mbelitx, M. Jauje, Jr. and A. de m, Tetrahedron O&t., 54DS (l’s86>. M. Jonea. Jr., Ph.D. Theais. Yale Univerelty, 1983. :: D. J. Burton and D. 0. Naae, J. Am. Chem. Sot.. 95, 8467 (1973). 8. R. A. Schneider and J. Yelnrald. J. Am. Chem. Sot., 89, 2023 (1987). 7. M. Obayaehl. B. Ito. K. Mateul and K. Kondo. Tetrahedron Lett., 23. 2323 (1982). 8. N. J. 5. Dewar and W. ThieI, J. Am. Chem. Sco., 99. 4999 (1977). 9. I. M. Schulnnn and a. J. Flenantck, J. Am. Chsm. Sco., 99. 9663 (LOID). em alac M. D. Neutcm and J. M. Schulaan, E., 94, 797 (1972). B. Zumrrld nnd W. Kutddgg. J. Am. Chem. Sm., 100, 2864 (19iS) and mferencee ti. 10. Bxothermicitiee, baeed cm the kncwn AH vahme for starting fmgpanta and pmducte (or Benetm 11. group equivalent eetimatee12) am E. -150 kcallmol and -86 kcal/moI. respectively. 12. 8. W. Beneon. wThermcchemlcal Kinetics,” John Wiley and Sona, New York, 1976. D. Q. Lsopdd, K. K. Murray. A. E. Stevau~ MIler and W. C. Lineberger. J. Chem. 13. II.

15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30.

B&h thie quentity and that for J. Phyx. Chmn.. a, 1625 (1970. valuee; however. the umertainti am sbnnar in nugnitude (a. 1 introduced by this approximation, and of coume. the lnaccumoles of the YNDO method far outweigh these smalI corrections. K. B. Wiberg and J. J. WslQbsld, J. Am. C~KQ. Taken fmm vahne _ and publbhed by: &.. 104. 5679 (1982). and K. B. Wiberg, Ibid., 105, 1227 (1983 ii Estimated from AHf (exptl) for the parent aniigroup equivalf$s. Estimated from AHf of 1.4-pentadiene and group equivalente. C. L. Bird. H. N. Frey and I. D. R. Stevens. Chem. Commun., 707 (1967). 1. D. R. Stevene. H. N. Rag and C. L. Bird, Anger. Cbmn., Int. Ed. RI@.. 7. 646 (19g8). 1. W. SohoeUer. J. Org. Chem.. 46, 2181 (1980). S. Hayaehi. T. &ai. N. IehBrawa. D. J. Burton, D. 0. N8ee and H. 8. K&g. Chem. L&t.. 983 (1979). D..Seyferth. 8. P. Hopper and 0. J. Murphy, J. Organwnetal. Chem.. 48, 201 (1972). W. H. Watanabe and L. B. Conlon. J. Am. Chem. Sot.. 78, 2828 (1057). L. K. Montgomery and J. W. Matt. 3. Am. Chem. 900.. 89, 6556 (1967). ., (Lo. 6460 <1958). R. I. HcagIin. D. G. Kubler and A. H. Montag and U. Burger, J. Am. C. W. J&fad, J. %mda. J.-C. B. Qehret. nT. Chem. Boo.. 98. 2585 (1978); C. W. Jefford, J. Rousrnhe and M. P/;9adopoulos. H&v.= 60 1557 (1985). &bay&i B. Ito K. Matrul and K. Kondo. Tetrahedron Lett.. 2323 (1082). W. R. Ddbier. Jr.,’ K. 9. Medinger. A. Qmenberg and J. F. Ih)lapin, Tetrahsdnn. 38, 2415 (1982). R. Smith and H. B. Simmons. 0 +%!?%I2 lfa:::(llkll (1981). A. Uchlda and K. Hata. J. Chem.