Cinchona Michael donor/acceptor

Michael donors and acceptors are common components in Brmsted base-mediated catalysis. Such transformations offer an uncomplicated route towards all-carbon quaternary stereocenters. In the most basic form, a,P-unsaturated aldehydes are highly reactive templates towards nucleophilic reactions. Under such conditions, mechanistic studies show no polymerization of the unsaturated aldehydes under cinchona alkaloid catalysis [10]. This absence of polymerization is a key mechanistic indicator that the quinucHdine nitrogen of the catalyst does not act as a nucleophilic promoter. Rather, the quinucHdine nitrogen acts, as predicted, in a Bronsted basic deprotonation-activation of various cyclic and acyclic... 

---