Development of a Catalytic Enantioselective Conjugate Addition of 1,3-Dicarbonyl Compounds to Nitroalkenes for the Synthesis of Endothelin-A Antagonist <b>ABT-546</b>. Scope, Mechanism, and Further Application to the Synthesis of the Antidepressant Rolipram
作者:David M. Barnes、Jianguo Ji、Michael G. Fickes、Michael A. Fitzgerald、Steven A. King、Howard E. Morton、Frederick A. Plagge、Margo Preskill、Seble H. Wagaw、Steven J. Wittenberger、Ji Zhang
DOI:10.1021/ja026788y
日期:2002.11.1
The enantioselective synthesis of endothelin-A antagonist ABT-546 has been accomplished via the discovery and development of a highly selective catalytic asymmetric conjugate addition of ketoesters to nitroolefins. Employing just 4 mol % bis(oxazoline)-Mg(OTf)(2) complex with an amine cocatalyst, we obtained the product nitroketone with 88% selectivity at the aryl-bearing stereocenter and in good yield
内皮素-A 拮抗剂 ABT-546 的对映选择性合成是通过发现和开发酮酯与硝基烯烃的高选择性催化不对称共轭加成来完成的。仅使用 4 mol% 双(恶唑啉)-Mg(OTf)(2) 配合物和胺助催化剂,我们在含芳基的立体中心以 88% 的选择性获得了产物硝基酮,并且在 13 mol 的规模范围内以良好的产率获得。描述了配体结构、金属盐和溶剂对反应的影响。对反应特别重要的是水含量。虽然在催化剂生成过程中需要水,但随后必须除去水以最大化立体选择性和反应性。该反应已扩展到其他二羰基底物,并且在硝基烯烃伙伴上可以容忍各种取代模式。该反应还用于合成抗抑郁药咯利普兰。还描述了有关反应机理的研究。