Chemistry of 1,3-Oxathianes. Reactivity of 2-Heterosubstituted 1,3-Oxathianes toward sec-Butyllithium and the Reaction of 2-(Trimethylsilyl)-1,3-oxathianyl Anion with Electrophiles

Article abstract of DOI:10.1021/jo00205a021

Investigation on the reaction of 2-heterosubstituted 1,3-oxathianes with sec-BuLi disclosed that all three possible reaction pathways, i, abstraction of the proton at C(2), ii, nucleophilic displacement at C(2), and iii, nucleophilic attack at the heteroatom, occurred depending on the heteroatom at C(2).With 2-(trimethylsilyl)-1,3-oxathiane (1a), sec-BuLi acts as a base to produce the corresponding anion 1b, whose reaction with electrophiles affords a variety of 2,2-disubstituted products.The reaction of 2-(trimethylsilyl)-1,3-oxathianyl anion (1b) with benzonitrilefollowed by hydrolysis gave rise to 2-benzoyl-1,3-oxathiane (17) instead of the expected 2-benzoyl-2-(trimethylsilyl)-1,3-oxathiane (16).Considearation of the mechanism for the formation of 17 has resulted in the development of an equivalent of acyl dianion generated from 1 molar equiv of base.