One-pot tandem enantioselective hydrogenation–hydroformylation synthesis of cyclic α-amino acids
作者:Euneace Teoh、Eva M. Campi、W. Roy Jackson、Andrea J. Robinson
DOI:10.1039/b209087m
日期:2003.1.20
Five- and six-membered cyclic amino acids can be prepared in good yield with high ee (>95%)
via tandem rhodium-DuPHOS catalysed asymmetric hydrogenation followed by a rhodium-catalysed hydroformylationâcyclisation sequence in a single pot. The synthesis can be achieved using Rh-DuPHOS as the sole catalyst.
Conotoxin analogues and methods for synthesis of intramolecular dicarba bridge-containing peptides
申请人:Robinson Andrea
公开号:US20070197429A1
公开(公告)日:2007-08-23
According to the present invention, there is provided a range of new conotoxin derivatives and methods for synthesizing these analogues and other intramolecular dicarba bridge-containing peptides, including dicarba-disulfide bridge-containing peptides.
Catalytic Asymmetric Hydrogenation of<b><i>α</i></b>-(Acetamido)acrylates Using TRAP Trans-Chelating Chiral Bisphosphine Ligands: Remarkable Effects of Ligand<b><i>P</i></b>-Substituent and Hydrogen Pressure on Enantioselectivity
作者:Ryoichi Kuwano、Masaya Sawamura、Yoshihiko Ito
DOI:10.1246/bcsj.73.2571
日期:2000.11
β-substituent and the ligand P-substituent as well as decreasing hydrogen pressure. The selectivity for the (R)-product in the reaction with EtTRAP-rhodium catalyst at 60 °C and 0.5 kg cm-2 of hydrogen pressure was as follows: R = H, 96% ee; R = Me, 92% ee; R = Ph, 77% ee; R = i-Pr, 57% ee. The remarkable steric and pressure effects caused a dramatic reversal of enantioselectivity in the reaction of methyl
用 [Rh(cod)2]BF4 和反式螯合手性双膦配体 (S,S)-2,2'-双 [( R)-1-(二烷基膦基)乙基]-1,1'-二茂铁[(R,R)-(S,S)-TRAPs]。在β-未取代或β-单取代的α-(乙酰氨基)丙烯酸酯[(E)-RCH=C(NHAc)CO2Me]的反应中,(R)-氢化产物的选择性随着底物β-空间需求的降低而增加取代基和配体 P 取代基以及降低氢压。在 60 °C 和 0.5 kg cm-2 氢气压力下与 EtTRAP-铑催化剂反应的 (R)-产物的选择性如下:R = H,96% ee;R = Me,92% ee;R = Ph,77% ee;R = i-Pr,57% ee。显着的空间和压力效应导致 2-(N-乙酰氨基) 肉桂酸甲酯 (R = Ph) 反应中对映选择性的显着逆转。例如,在 60 °C 和 0.1 kg cm-2 氢气压力下使用 EtTRAP 的选择性为 87%
Application of Chiral Mixed Phosphorus/Sulfur Ligands to Enantioselective Rhodium-Catalyzed Dehydroamino Acid Hydrogenation and Ketone Hydrosilylation Processes
作者:David A. Evans、Forrest E. Michael、Jason S. Tedrow、Kevin R. Campos
DOI:10.1021/ja012639o
日期:2003.3.1
Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of alpha-acylaminoacrylates
A highly enantioselective synthesis of cyclic α-amino acids involving a one-pot, single catalyst, tandem hydrogenation–hydroformylation sequenceElectronic supplementary information (ESI) available: experimental information. See http://www.rsc.org/suppdata/cc/b2/b200374k/
作者:Euneace Teoh、Eva M. Campi、W. Roy Jackson、Andrea J. Robinson
DOI:10.1039/b200374k
日期:2002.4.19
Tandem enantioselective hydrogenation followed by a hydroformylationâcyclisation sequence leading to cyclic α-amino acids with eeâs >95% can be achieved in a single pot, one catalyst system by successive reactions of prochiral dienamide esters with H2 followed by H2/CO using Rh(I)-DuPHOS.