Dienamine Activation in Enantioselective Intramolecular Rauhut-Currier Reactions

Significance

Christmann and co-workers report an asymmetric intramolecular Rauhut-Currier reaction. In the presence of prolinol silyl ether 1, the starting α,β-unsaturated aldehydes 2 were converted into the corresponding cyclopentenones 3 in reasonable yields and enantioselectivities of up to er = 98:2. The proposed mechanism involves the activation of 2 by catalyst 1, resulting in a di­enamine intermediate, showing d^²-reactivity in the following intramolecular Michael addition. Eventually, isomerization of the double bond and hydrolysis lead to products 3 and regeneration of the catalyst.