Dipeptidic Proline Amide–Isothiouronium Salt Organocatalysts for Enantiodivergent Conjugate Addition Reactions Between Aldehydes and Nitroolefins

Abstract

We rationally designed and successfully developed novel dipeptidic proline amide–isothiouronium catalysts for asymmetric conjugate addition reactions between various aldehydes and nitroolefins, which generated 1,4-addition products with up to 95% yields, 92:8 syn-diastereoselectivity, and 96% enantiomeric excess. The catalysts, which were prepared via simple methylation of the corresponding thiourea, can provide the desired enantiomeric syn-1,4-adducts by exchanging the configuration of the N-terminal proline moiety.