Complementary Stereochemical Outcomes in Proline-Based Self-Regenerations of Stereocenters

Stereoselective alkylations of proline-based amino amides are described, where high levels of either a cis or trans configuration can be attained simply by the choice of the aminal group. Isobutryaldehyde-derived aminals provide the cis configuration, while 1-naphthaldehyde-derived aminals engender the complementary trans configuration.