Synthesis of Unnatural Amino Acids via Suzuki Cross-Coupling of Enantiopure Vinyloxazolidine Derivatives
作者:Mark Sabat、Carl R. Johnson
DOI:10.1021/ol005645i
日期:2000.4.1
S)-alpha-Amino alcohols and alpha-amino acids, including 4-methoxyhomophenylalanine, with a variety of unnatural side chains have been synthesized via palladium-catalyzed cross-coupling Suzuki reactions. The key buildingblocks 1 and 2, synthesized from the common achiral precursor 2-butene-1,4-diol, were made enantiopure utilizing a Pseudomonas cepacia lipase-catalyzed kinetic resolution. The optimal
Cationic Pd(II) catalysts generated from chiral biphenyl diphosphine complexes or from COP-Cl promote enantioselective cyclization of E- and Z-configured allylic bis-trichloroacetimidates to highly enantioenriched 2-trichloromethyl-4-vinyloxazoline. This represents an exclusive example for olefin amination in high yield and enantioselectivity with trichloroacetimidate as the N-nucleophile by using