An Enantioselective Synthesis of (<i>S</i>)-(+)-3-Aminomethyl-5-methylhexanoic Acid via Asymmetric Hydrogenation
作者:Mark J. Burk、Pieter D. de Koning、Todd M. Grote、Marvin S. Hoekstra、Garrett Hoge、Rex A. Jennings、William S. Kissel、Tung V. Le、Ian C. Lennon、Thomas A. Mulhern、James A. Ramsden、Robert A. Wade
DOI:10.1021/jo034397b
日期:2003.7.1
A concise enantioselective synthesis of (S)-(+)-3-aminomethyl-5-methylhexanoic acid (1, Pregabalin) has been developed. The key step is the asymmetric hydrogenation of a 3-cyano-5-methylhex-3-enoic acid salt 2 with a rhodium Me-DuPHOS catalyst, providing the desired (S)-3-cyano-5-methylhexanoate 3 in very high ee. Subsequent hydrogenation of the nitrile 3 with a heterogeneous nickel catalyst provides
Highly Selective Asymmetric Hydrogenation Using a Three Hindered Quadrant Bisphosphine Rhodium Catalyst
作者:Garrett Hoge、He-Ping Wu、William S. Kissel、Derek A. Pflum、Derek J. Greene、Jian Bao
DOI:10.1021/ja048496y
日期:2004.5.1
synthesis of both enantiomers of ligand2 and rhodium complex 5 is presented. The crux of the synthesis is a chiral HPLC separation of the enantiomers of 4. Rhodium complex 5 possesses three hindered quadrants in the steric environment within which a substrate binds. Evidence is presented that this configuration leads to high enantioselectivity (>99% ee) for rhodium-catalyzed asymmetric hydrogenation of