Potassium triisopropylsilanethiolate: Vinyl and aryl sulfides through Pd-catalyzed cross coupling

Terrahednm Lmers, Vol. 35, No. 20, pp. 32253226, 1994 Elsevia ScienceLtd Printedin Great Britain 0040-4039/‘94 $6.006).00

VINYL AND ARYL OLATE: TRIISOPROPYL8m TI-IROUGH PD-CATALYZED CROSS COUPLING

POTASSIUM

SULFIDES

Anil M. Rane.’ Edgar I. Miranda’ and John A. Soderquist* Department of Chemistry. University of Puerto Rico Rio Piedras. Puerto Rico 00931.

Abstract: Vinyl and aryl halides are efliciedly converted, under Pd catalysis, with KSTIPS (I) to the corresponding silyl sulJies (2, 31. The naphthyl derivative was easily hydrolyzed to the mercaptan 4, or alkylated or alkenylated to provide unsymmetrical surides (6 61. A common

feature

is also important employed

of many

in chemical

to introduce

the known

Pd-catalyzed

a silylthio.

rather

this functionality coupling

than ArS.

a variety

of alternative

approach

to unsymmetrical

Recently. from TIPSCl KH.6 The to both

we have

reagent

stabilily

catalyzed

halides

would

substrates.

with

enable

synthetic

is a powerful

the silyl group

to be subsequently enhance

than

the introduction replaced

the versatility

f HSTIPS ) can be readily

that triisopropylsilanethfol

nucleophile

cleavage

to undergo

to produce

more convenient

However.

a feature which would markedly

functionality

have been successfully

none appear

aryW.hiolates.’

to its stable. which

crystalline

is readily

by organometallic

the coupling

reagenls

process

of by

of this

alkenyl

and 2’

halides

of these TIPS derivatives

that

observed

lo

prepared

1, (95%) with

salt,

by both

resistance

suggested

previously

alkenyl and aryl halides were selected. the corresponding

potassium

alkylated

silyl alkyl sulRdes cleanly. The unusual

and

the sulRde

methods

sullides.

discovered

Thus. nine representative silanethiolated

and pharmaceuticals.

into organic

(98O/b)and converted

to provide

hydrolysis

necessary

group,

products

While numerous

of vinyl

substituents.

and LiSH

and tosylates

natural

synthesis.’

only

1 might

possess

the

for the arylthiolates.

and all were found to be elI’iciently

(2) or aryl

(3) silyl

sulRdes

under

the Pd-

conditions.6

3 These results, which are presented in Table 1. reveal that the reaction proceeds with complete retention of configuration in the case of the vinyl derivatives examined (cJ entries 2 and 3) and give good enhance BrC,H,NO,

to excellent

product

the rate of coupling occurs

yields

even on a small reaction

of 1 with aryl bromides

in 6 h at 25 “C in the absense

(cj

scale.

entries

Eleclron-withdrawing

57.8).

No reaction

groups

of 1 with p-

of the Pd catalyst.

We chose to demonstrate the versatility of these silyl sullldes by elTecting the deprotection of 3225

3226

Table entry 1 2 3 4 5 6 7” 8’ 9’

1. Alkenyl

and Aryl Silyl Sulfides

R, R’. R’

Ar

X

Me, Me, H n-Pr. H. H H. n-Pr. H H. H, Me

Ph 1-Naph C,H,(NO,-P) C,H,(OMe-p) 2-W

time (h)

Br I I Br Br Br Br Br Br

from

1.

Product

36 2 2 1.5 2 5 0.25 12 12

yield

2a 2b 2c 26 3a 3b 3c 36 3t

84 66 89 92 77 61 93 68 79

a The aryl bromide was reiluxed 1 h wilh the catalyst prior to the addition of 1.' 3b

(CsF/DMF

hydrolysis

to

intermediate bromide

we

4

give

5

bromide are very

25

“Cl

(73%).

thiolate

to

isopropenyl of which

8 h.

is

(65%) clean

or

suggesting

stable

required

for

a

with

coupled

its the ally1

with

6 (550/b).’ all

reactions.

However,

6 from 26 and l-

were unable to prepare under

by

Alternatively, alkylated

to provide

bromonaphthalene that

followed

similar

conditions,

thio-enolates

successful

cross

are

3b

coupling \

process.

* NII’Phglq

REFERENCES

AND

NOTES

1. Graduate Student supported by the NSF EPSCoR Program of Puerto Rico. 2. U. S. Department of Education Graduate Fellowship (P2OOA90203). 3. (a) Mukaiyama. T.: Kamio. K.: Kobayashi. S: Takei. H. Bull. Chern. Sot. Jpn. 1972. 45. 3723. (b) Trost. B. M.: Hirol. K.; Kurozumi. S. J. Am. C&m. Sot. 1975. 97. 438. (c) Oshima. K.: Shimoji, K.: Takahashi, H.: Yamamoto. H.: Nozakl. H. J. Am Chem. Sot. 1973. 95, 2694. (d) Cookson. R. C.: Parson. P. J. J. Chem. Sot. Chem Commun. 1976, 990. (e) Cookson, R. C.; Parson, P. J. J. Chem. Sot. Chem Commun. 1978. 821. (6 Muthukrishnam, R.; Schlosser. M. Helo. C/tan. Ada. 1976, 59. 13. (g) Brown, C. A. J. Org. Chem. 1978, 43, 3083. (h) Le Nocher, A.-M.: Metzner. P. Telrahedron Lett. 1992. 33. 6151. 4. Murahashi, S.: Yamamura, M.; Yanaglsawa. K.; Mita, N.; Kondo, K. J. Org. Chem. 1979. 44, 2408. 5. Miranda, E. I.: Diaz, M. J.: Rosado, I.; Soderquist, J. A. (previous paper). The authors wish to thank Mr. M. J. Diaz for preparing the 1 used in this study. 6. Representative procedure: To a well-stirred solutlon of Pd(PPh,), (0.070 g. 0.6% mole), cis-1-iodo-1-pentene (0.411 g. 2.1 mmol) in C,H, (10 mL) was added 1 (0.457 g. 2 mmol) in THF (2-4 mL). After 2 h at reflux, H,O (10 mL) and hexanes (IO mL) were added. The organic layer was washed with H,O (2 x 10 mL). dried over Na,SO,. concentrated and the residue was loaded onto an alumina (3 g) column and flash chromatographed with hexanes. Concentration affords 0.459 g (89%) of 2c. ‘H NMR (CDCl,) 6 0.93 (t, J = 7.2 Hz. 3H), 1.12 (d. J = 7.2 Hz. 18 H). 1.26 (m. 3H). 1.43 (sext. J = 7.2 Hz. 2H). 2.25 (dq. J = 7.5, 1.1 Hz. 2H). 5.69 (dt. J = 9.1. 7.2 Hz, lH), 5.98 (dt. J = 9.1. 1.1 Hz, IH); 13C NMR (CDCl,) 6 12.7. 18.4 (TIPS), 13.8. 22.1. 30.7. 117.4, 134.2; IR (TF) 1610 cm”: MS m/z (rel abundance) 258 (Mt. 29). 215 (86). 7. Aukharleva, R. G.; Danllova, T. A.; Anisimov. A. V.: Viktorova. E. A. Kim. Geterotskkf Socdin 1981. 5. 611. (Received in UsA 8 September

1993; revised 21 February 1994, accepted 22 Fehary

1994)