Chlorodimethylsilane

ClMe2SiH

[1066-35-9]  · C2H7ClSi  · Chlorodimethylsilane  · (MW 94.62)

(intramolecular hydrosilation of allyl alcohols, homoallyl alcohols, allyl amines, and a-hydroxy ketones for the regio- and stereoselective synthesis of polyols and amino alcohols)

Physical Data: bp 35-36 °C; mp -111 °C; n20D 1.3830; d 0.852 g cm-3.

Solubility: sol common aprotic organic solvents.

Form Supplied in: neat liquid.

Handling, Storage, and Precautions: moisture sensitive and corrosive. Must be stored under nitrogen in a tightly capped bottle in a freezer and transferred or weighed quickly via syringe. This reagent should be handled in a fume hood.

Intramolecular Hydrosilation of Allyl and Homoallyl Alcohols.

For a detailed description of the intramolecular hydrosilation-oxidation sequence, see 1,1,3,3-Tetramethyldisilazane. 1,1,3,3-Tetramethyldisilazane and N,N-Diethylaminodimethylsilane are frequently employed for preparation of hydrodimethylsilyl ethers for the intramolecular hydrosilation of allyl and homoallyl alcohols. Chlorodimethylsilane in combination with a tertiary amine such as Triethylamine is another useful reagent for the synthesis of hydrodimethylsilyl ethers, especially for large scale preparations.1

Other chlorodiorganosilanes (ClR2SiH) such as Chlorodiisopropylsilane (Cl(i-Pr)2SiH),2 Chlorodiphenylsilane (ClPh2SiH),3 and 1-chloro-1-silacyclohexane ((CH2)5SiClH),4 are also useful reagents for intramolecular hydrosilation, including catalytic asymmetric intramolecular hydrosilation.3,4 These bulky hydrosilanes have some advantages over ClMe2SiH in these reactions, since the silylated intermediates are less moisture sensitive, are more easily handled, and can lead to higher stereoselectivity in the alkene hydrosilation step.

Intramolecular Hydrosilation of Allyl Amines.

The amino group of an allyl amine is silylated with chlorodimethylsilane, and then the resulting silazane is subjected to standard platinum-catalyzed cyclization and oxidation steps to form a syn-2-amino alcohol (eq 1). Exclusive formation of the four-membered cyclic product and the high stereoselectivity should be noted.5

Intramolecular Hydrosilation of Carbonyl Groups.

Catalytic asymmetric intramolecular hydrosilation of the carbonyl group of an a-hydroxy ketone has been attained by using chlorodimethylsilane as the silylating agent and a rhodium catalyst containing an optically active bidentate ligand (eq 2).6

In addition, chlorodiisopropylsilane is a useful reagent for Lewis acid catalyzed intramolecular hydrosilation of b-hydroxy ketones7 and for fluoride ion induced reduction of esters.8 It may also be mentioned that chlorodi-t-butylsilane is used in highly stereoselective intramolecular ionic hydrogenations of hydroxy alkenes.9


1. Tamao, K.; Nakagawa, Y.; Ito, Y. OS, 1995, in press.
2. Anwar, S.; Davis, A. P. Proc. R. Ir. Acad. 1989, 89B, 71.
3. Tamao, K.; Tohma, T.; Inui, N.; Nakayama, O.; Ito, Y. TL 1990, 31, 50, 7333.
4. Bergens, S. H.; Noheda, P.; Whelan, J.; Bosnich, B. JACS 1992, 114, 2121.
5. Tamao, K.; Nakagawa, Y.; Ito, Y. JOC 1990, 55, 3438; JACS 1992, 114, 218.
6. Burk, M. J.; Feaster, J. E. TL 1992, 33, 2099.
7. Anwar, S.; Bradley, G.; Davis, A. P. JCS(P1) 1991, 1383.
8. Davis, A. P.; Hegarty, S. C. JACS 1992, 114, 2745.
9. McCombie, S. W.; Ortiz, C.; Cox, B.; Ganguly, A. K. SL 1993, 541.

Kohei Tamao,

Kyoto University, Japan



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