Lanthanum-Catalyzed Asymmetric Michael Reactions

Significance

A catalytic asymmetric Michael reaction of malonates to α,β-unsaturated N-acyl­pyrroles is described using a lanthanum catalyst and a designed Ph-substituted linked BINOL ligand. Alkyl, branched alkyl, alkenyl, and β-aryl N-acylpyrroles are all suitable substrates and give good yields and ee values, although the β-aryl and branched substrates require higher catalyst loadings (20 mol%). Previously unreported transformations of the amide-substituted N-acylpyrrole products to esters, thioesters and other amides are shown with conversions in good yields. Cyclization of the product with sodium borohydride is also attainable in high yield.