Diastereoselectivity Switch in the Pd(0)/InI-Mediated Reactions of β-Lactams with Aldehydes: An Entry into Nonracemic Semiprotected (3 E)-2,6-Enediols

J Org Chem. 2019 Oct 4;84(19):12268-12280. doi: 10.1021/acs.joc.9b01471. Epub 2019 Sep 18.

Abstract

The switch from N-methylimidazole (N-MI) to the Et3N N-ligand efficiently alters diastereoselectivity in Pd(0)/InI-mediated allylations of aldehydes with β-lactam-derived organoindiums. As a result, (3E)-selective allylations and crotylations of a variety of aliphatic and (hetero)aromatic aldehydes with differently substituted chiral ε-amido-allylindiums were developed. Depending on the relative β-lactam configuration, the reactions occur under kinetic or thermodynamic control, with effective remote 1,5- or 1,4,5-asymmetric induction to afford a diversity of previously unavailable (3E)-2,5-syn-2,6-anti-, (3E)-2,5-anti-2,6-anti-, and (3E)-2,5-anti-2,6-syn-substituted enediols, amino alcohols, and homoallylic alcohols in modest to high yields and with moderate to excellent diastereoselectivity. The effect of the N-ligand as well as β-lactam and aldehyde structures on the yield and stereoselectivity was investigated.

Publication types

  • Research Support, Non-U.S. Gov't