Molander Gary A, Burke Jason P, Carroll Patrick J
Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
J Org Chem. 2004 Nov 12;69(23):8062-9. doi: 10.1021/jo048782s.
A series of chiral, cyclopropane-based phosphorus/sulfur ligands have been synthesized and evaluated in the palladium-catalyzed allylic alkylation of 1,3-diphenylpropenyl acetate with dimethyl malonate. Variation of the ligand substituents at phosphorus, sulfur, and the carbon backbone revealed 24d to have the optimal configuration for this reaction, giving the product in high yield and with good enantioselectivity (93%). A model for the observed enantioselectivity is discussed within the context of existing models, using X-ray crystallographic data, solution-phase NMR studies, and the absolute stereochemistry of the products. Selected ligands were also evaluated in the palladium-catalyzed intermolecular Heck reaction and the rhodium-catalyzed hydrogenation of a dehydroamino acid.
一系列基于环丙烷的手性磷/硫配体已被合成，并在钯催化下用丙二酸二甲酯对1,3 - 二苯基丙烯基乙酸酯进行烯丙基烷基化反应中进行了评估。磷、硫和碳主链上配体取代基的变化表明，24d对于该反应具有最佳构型，能以高产率和良好的对映选择性（93%）得到产物。利用X射线晶体学数据、溶液相核磁共振研究以及产物的绝对立体化学，在现有模型的背景下讨论了观察到的对映选择性模型。还在钯催化的分子间Heck反应以及铑催化的脱氢氨基酸氢化反应中对选定的配体进行了评估。
