Efficient Mukaiyama Aldol Reaction by Silver(I) Carboxylate-Bis(phosphine) Catalysts
Munetaka OHKOUCHI, Dai MASUI, Motowo YAMAGUCHI and Takamichi YAMAGISHI*
Department of Applied Chemsitry, Graduate School of Engineering, Tokyo Metropolitan University; Minami-ohsawa, Hachioji-shi 192-0397 Japan
Silver (I) carboxylate-BINAP complex, water tolerant and air-stable, is a highly efficient catalyst for Mukaiyama aldol reaction using silyl enol ethers or ketene silyl acetals as nucleophiles. The Mukaiyama aldol reaction of aldehydes or keto esters in DMF afforded aldol products quantitatively in a short reaction time by this silver (I) carboxylate-BINAP catalyst. Using ketene silyl acetals, aliphatic ketones also gave the aldol products in high yields, however, with aromatic ketones both aldol reaction and silyl transfer reaction were observed. The silver (I) carboxylate-BINAP catalyst acts as a good catalyst for Mukaiyama Michael addition of α,β-unsaturated ketones. The catalyst strongly activates nucleophiles to cause the aldol reaction easily.