Naomasa Sato

Nickel Catalyzed Copolymerization of Ethylene and Alkyl Acrylates

Ni(II) complexes bearing an o-bis(aryl)phosphinophenolate ligand were synthesized as catalysts for copolymerization of ethylene and alkyl acrylates. When the P-bound aryl group was 2,6-dimethoxyphenyl group, one of the oxygen atoms in the methoxy groups coordinated to the nickel center on its apical position. This complex was a highly active catalyst without any activators to give highly linear and high molecular weight copolymers. The structures of the copolymers were determined by 1H and 13C NMR to clarify that the alkyl acrylate comonomers were incorporated in the main chain and that the structures of the copolymers were significantly influenced by the structure of the aryl group in the ligand.

Enantioselective synthesis of L- and D-isoserine via asymmetric hydrogenation of methyl N-phthaloyl-3-amino-2-oxopropanoate

Abstract L - and D -isoserine were synthesized enantioselectively via asymmetric hydrogenation of 3-amino-2-oxoester 5 catalyzed by [RuCl(binap)(benzene)]CI. Recrystallization and deprotection of (S)-6 (81% ee) afforded enantiomerically pure L -isoserine. The enantioface selection by the catalyst was opposite to that observed in asymmetric hydrogenation of other 2-oxoesters, such as methyl phenylglyoxylate and methyl 2-oxocyclohexylacetate.