Organocatalytic Asymmetric Vinylogous Mukaiyama Aldol Reaction

Significance

The first organocatalytic asymmetric hydrogen-bond-catalyzed vinylogous Mukaiyama aldol reaction has been developed. Addition of silyldienol ether 1 to aldehydes in the presence of 20 mol% of TADDOL 2 results in the formation of products of type 3 in good yield and enantioselectivity. Glyoxalate esters, α,β-unsaturated aldehydes, heterocyclic aldehydes, as well as electron-poor aromatic aldehydes are converted regiospecifically into the corresponding vinylogous aldol products. In addition, a model illustrating the mode of noncovalent activation of the electrophile by the chiral diol 2 to explain the observed absolute configuration is given.