An Unusual Dependence of Counterion During Wittig Methylenation of Bis-Heteroaryl Ketones

Article abstract of DOI:10.1016/0040-4039(95)02016-I

Attempted Wittig methylenation of some bis-heteroaromatic ketones (8, 11 and 13) using MeP⁺Ph3Br^- and n-BuLi gave none of the desired olefin.However, when KtBuO was used as the base for generation of the ylide, efficient olefination of these ketones was observed.A possible mechanistic pathway for this interesting but unprecedented observation is proposed.