Trapping of oxonium ylides with a number of Michael acceptors via a 1,4-addition fashion has been investigated. Benzylidene Meldrum's acids and 4-oxo-enoates have been found to be matched components as suitable Michael acceptors for the transformation. Thus, Rh 2 (OAc) 4 -catalyzed three-component reactions of diazo compounds, alcohols, and benzylidene Meldrum's acids/4-oxo-enoates gave corresponding a-hydroxyesters in good yield with high to excellent diastereoselectivity. Synthetic utility of this efficient method was demonstrated by conversion of the addition product to a g-butyrolactone through simple procedures.

It is revealed that the title compounds are suitable Michael acceptors for interception of oxonium ylides generated from diazo compounds and alcohols via a 1,4-addition mode. -(HAN, X.; GAN, M.; QIU, H.; JI, J.; ZHANG, X.; JIANG*, L.; HU, W.; Synlett 2011, 12, 1717-1722, http://dx.