Asymmetric Addition of α,α-Dicyanoalkenes to α,β-Unsaturated Ketones

Significance

The authors of this paper were originally interested in discovering a domino Michael-Michael addition of α,α-dicyanoalkenes to α,β-unsaturated ketones. They found the first step to proceed smoothly when chiral, primary amines were employed as catalysts, but the reaction stopped in the case of the bicyclic substrates shown in the upper part of the scheme. In less-hindered systems, the desired reaction sequence took place, but was then followed by a retro-Michael reaction to yield the enone product. The enones could also be obtained starting from the bulkier products of the first Michael reaction upon treatment with the less-hindered benzylamine tri­fluoroacetic acid salt in very high yields. Both enantiomers of the products are accessible through the use of either catalyst A or B.