Construction of Highly Functionalized Diazoacetoacetates via Catalytic Mukaiyama−Michael Reactions

Functionalized diazo acetoacetates are prepared by an efficient Mukaiyama−Michael reaction between methyl 3-(trialkylsilanoxy)-2-diazo-3-butenoate and α,β-unsaturated enones. Vinyl ether and ketone derivatives are both accessible in good to excellent yield through this methodology. The mild Lewis acid zinc(II) triflate is the optimal catalyst, and its loading can be as low as 0.1 mol %. In addition, zinc triflate was also found to be a superior catalyst for the related Mukaiyama−aldol reaction.