Highly efficient synthesis of beta-amino acid derivatives via asymmetric hydrogenation of unprotected enamines.

Highly efficient synthesis of chiral beta-amino acid derivatives via asymmetric hydrogenation.

The Rh-TangPhos complex is an efficient hydrogenation catalyst for making chiral beta-amino acid derivatives. With the Rh-TangPhos system, high enantioselectivities (up to 99.6%) and turnover numbers have been obtained in the hydrogenation of E/Z isomeric mixtures of both beta-alkyl and beta-aryl beta-(acylamino)acrylates. [reaction: see text]

Brønsted acid activation strategy in transition-metal catalyzed asymmetric hydrogenation of N-unprotected imines, enamines, and N-heteroaromatic compounds.

Asymmetric hydrogenation plays an important role in organic synthesis, but that of the challenging substrates such as N-unprotected imines, enamines, and N-heteroaromatic compounds (1H-indoles, 1H-pyrroles, pyridines, quinolines, and quinoxalines) has only received increased attention in the past three years. Considering the interaction modes of a Brønsted acid with a Lewis base, Brønsted acids...

Efficient rhodium-catalyzed asymmetric hydrogenation for the synthesis of a new class of N-aryl beta-amino acid derivatives.

[reaction: see text] N-Aryl beta-amino esters were obtained by asymmetric hydrogenation of a new class of N-aryl beta-enamino esters. High conversions and up to 96.3% ee values were achieved with a Rh-TangPhos catalyst.

Iridium-catalyzed asymmetric hydrogenation of cyclic enamines.

The first highly enantioselective iridium-catalyzed hydrogenation of cyclic enamines has been developed. This new reaction provided an efficient method for the synthesis of optically active cyclic tertiary amines including natural product crispine A.

Synthesis of N-aryl β-amino acid derivatives via asymmetric hydrogenation