(+ -)-3-METHYL-1,1-DIPHENYL-2-BUTYL 3-ACETAMIDOCROTONATE AND ITS HYDROGENATION PRODUCT/

Synthesis of (+/-)-3-methyl-1,1-diphenyl-2-butyl beta-acetamidobutanoa te, C23H29NO3, (10), With high diastereoisomeric excess was achieved b y asymmetric hydrogenation of the stereogenic title compound, C23H27NO 3, (9), in which the chirality is present in the ester part. The aceta midocrotonate (9) is planar and delimits a pro-R and a pro-S face. An intramolecular hydrogen bond between the amino group and the carboxyla te group is essential to ensure planarity. One of the phenyl rings of the ester hinders one face. The hydrogenation occurs by the opposite f ace as proved by the crystal structure of its product of hydrogenation , (10).