Generation of Stereochemically Defined Tetrasubstituted Enolborinates By 1,4-Hydroboration of α,β-Unsaturated Morpholine Carboxamides with (Diisopinocampheyl)borane

by Christophe Allais, Andy S. Tsai, Philippe Nuhant, William R. Roush*

On all fours: The title reaction with (Ipc)₂BH provides tetrasubstituted enolborinates which undergo aldol reactions with aldehydes to form products with all-carbon quaternary centers with exceptional diastereo- and enantioselectivity. A change to the substitution pattern of the starting amide leads to either diastereomer of the α-methyl-α-ethyl-β-hydroxy carboxamide (1 or 2).

Angewandte Chemie International Edition

DOI:10.1002/anie.201307302