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Unusual amino acids IV. Asymmetric synthesis of thienylalanines

1993; Elsevier BV; Volume: 4; Issue: 8 Linguagem: Inglês

10.1016/s0957-4166(00)80424-3

1362-511X

Christian Döbler, H.‐J. KREUZFELD, H. W. Krause, Manfred Michalik,

Asymmetric Synthesis and Catalysis

Abstract (Z)-2-N-Acylamino-3-thienyl-acrylic acids and their esters were prepared by known procedures and hydrogenated to the corresponding optically active 2-N-acetyl(or benzoyl)-3-(2- or 3-thienyl)-alanines with optical yields up to 90% using the rhodium complexes of “PROPRAPHOS” 6a,b and O,N-bis(diphenylphosphino)-2-exo-hydroxy,3-endo-methylamino-norborane 6c as chiral catalysts. Recrystallization and deacylation of the obtained amino acid derivatives yields the optically pure hydrochlorides of the thienylalanines and the free amino acids.