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.
Catalytic asymmetric hydrogenation of β-substituted α,β,γ,δ-unsaturated amino acids
作者:Mark J. Burk、Karen M. Bedingfield、William F. Kiesman、John G. Allen
DOI:10.1016/s0040-4039(99)00437-2
日期:1999.4
The Rh-DuPHOS and Rh-BPE catalyzed hydrogenation of β-substituted α,β,γ,δ-unsaturated amino acids establishes two contiguous stereogenic centers simultaneously. Both high regioselectivity and good to excellent enantioselectivity have been demonstrated in this process leading to β-branched allyl glycine derivatives. Enamide geometry was found to influence stereoselectivity. Studies aimed at defining