A highly enantioselective asymmetric hydrogenation route to β-(2R,3S)-methyltryptophan
摘要:
Asymmetric hydrogenation of a protected (Z)-dehydro-beta-methyltryptophan derivative 2 with (R,R)-Me-DuPHOS-Rh catalysis was achieved in 97 % ee. Deprotection then afforded (2R,3S)-beta-methyltryptophan 1. (C) 1998 Elsevier Science Ltd. All rights reserved.
A convenient cross-coupling route to α,β,γ,δ-unsaturated amino acids
作者:Mark J. Burk、John G. Allen、William F. Kiesman、Karen M. Stoffan
DOI:10.1016/s0040-4039(97)00065-8
日期:1997.2
β-Bromoenamide esters are coupled stereospecifically to vinylboronic acids via a palladium-catalyzed Suzuki reaction. This cross-coupling proceeds under mild conditions with Pd(OAc)2 in 95% EtOH at 50 °C and produces amino acids with 1,3-diene side chains in high yields.