A novel reduction of alcohols and ethers with a HSiEt3/catalytic B(C6F5)3 system

The primary alcohols 1a-d and ethers 4a-b were effectively reduced into the corresponding hydrocarbons 2 by HSiEt3 in the presence of catalytic amounts of B(C6F5)(3). The secondary alkyl ethers 4g,h underwent cleavage and/or reduction under similar reaction conditions to produce either the silyl ether 3k or the corresponding alcohol 5b upon subsequent deprotection with TBAF. The secondary alcohols (1g,h) and tertiary alcohol 1i, as well as tertiary alkyl ether 4i, did not react with the HSiEt3/(B(C6F5)(3) reducing reagent at all. The following relative reactivity order of substrates was found: primary>>secondary>tertiary. The methyl aryl ethers 4c-e and alkyl aryl ether 4f were smoothly deprotected to give the corresponding silyl ethers 3b,h-j in nearly quantitative isolated yields. (C) 1999 Elsevier Science Ltd. All rights reserved.