Beyond benzyl grignards: facile generation of benzyl carbanions from styrenes.

摘要: Benzylic functionalization is a convenient approach towards the conversion of readily available aromatic hydrocarbon feedstocks into more useful molecules. However, formation carbanionic benzyl species from halides or similar precursors far trivial. An alternative direct reaction styrene with suitable coupling partner, but these reactions often involve use precious-metal transition-metal catalysts. Herein, we report facile and generation reactive anionic styrenes. A Cu(I)-catalyzed Markovnikov hydroboration styrenic double bond by using bulky pinacol borane source followed treatment KOtBu to facilitate sterically induced cleavage C-B produce benzylic carbanion. Quenching this intermediate variety electrophiles, including CO(2), CS(2), isocyanates, isothiocyanates, promotes C-C at carbon atom. The utility methodology was demonstrated in three-step, two-pot synthesis nonsteroidal anti-inflammatory drug (±)-flurbiprofen.