Ring Opening of Epoxides by Pendant Silanols

We present a new ring-opening reaction of epoxides by pendant silanols, catalyzed by either Ph3C+BF4- or BINOL-phosphoric acid. Silanol epoxides derived from trans-allylic alcohols, cis-allylic alcohols, trans-homoallylic alcohols, and cis-homoallylic alcohols were all compatible and gave products from either endo- or exo-ring opening. With silanol epoxides derived from 4-alkenyl silanols, an unusual rearrangement to tetrahydrofuran products was observed. The utility of this methodology was demonstrated in a short preparation of protected D-arabitol.

Automated summary

This study presents a new ring-opening reaction of epoxides catalyzed by pendant silanols. Different types of silanol epoxides derived from various allylic alcohols were compatible and yielded products with either endo- or exo-ring opening. An unusual rearrangement to tetrahydrofuran products was observed with one type of silanol epoxide derived from 4-alkenyl silanols. The utility of this methodology was demonstrated in a short preparation of protected D-arabitol.