Key points are not available for this paper at this time.
-heterocyclic carbene (NHC) catalysis has presented new opportunities for enantioselective reaction development. Recent findings illustrate that Lewis acids can play an important role in homoenolate annulations by: enhancement of the reactivity, reversal of the diastereo- or regioselectivity, and activation of previously inactive electrophiles. Additionally, the incorporation of a Lewis acid into Brønsted base-catalyzed conjugate addition allowed for an increase in yields.
Cohen et al. (2011) studied this question.