New strategies for protecting group chemistry: synthesis, reactivity, and indirect oxidative cleavage of para-siletanylbenzyl ethers.

ABSTRACT

Reported herein is a new entry in the growing arsenal of arylmethyl ether protecting groups. The para-siletanylbenzyl (PSB) ether is electronically similar to the benzyl ether. Cleavage of the PSB ether is accomplished under mild conditions--involving alkaline hydrogen peroxide--that are unique among cleavage protocols for arylmethyl ethers. Furthermore, the PSB group affords the user new flexibility in the implementation of protecting group strategies that revolve around multiple arylmethyl ether protecting groups. In addition to hydrogen peroxide-based cleavage protocols, conversion of a PSB ether into a para-methoxybenzyl (PMB) ether and assembly of a PSB ether from a pre-existing para-bromobenzyl (PBB) ether are described. Finally, a new reagent for installing PSB ethers under neutral "mix and heat" conditions is reported.