text]. The first general and highlyenantioselective organocatalytic Friedel-Craftsalkylation of indoles with simple alpha,beta-unsaturated ketones has been accomplished. Central to these studies has been the identification of a new catalyst amine salt, in which both the cation and the anion are chiral, that exhibits high reactivity and selectivity for iminium ion catalysis.
Electron-Withdrawing, Biphenyl-2,2′-diol-Based Compounds for Asymmetric Catalysis
作者:Elisa G. Gutierrez、Eric J. Moorhead、Eva H. Smith、Vivian Lin、Laura K. G. Ackerman、Claire E. Knezevic、Victoria Sun、Sharday Grant、Anna G. Wenzel
DOI:10.1002/ejoc.201000070
日期:——
Facile synthetic routes to a chiral chloro-substituted biphenyl-2,2′-diyl hydrogen phosphate and a chiral O,O-biphenyl-2,2′-diyl phosphoramidothioate are described. The performance of these compounds as catalysts for the hydrophosphonylation of imines and the Friedel–Crafts alkylation of indole was investigated. In the latter reaction, the chloro-substituted phosphoric acid derivative was found to
Asymmetric Friedel-Crafts Alkylation of Indole with Chalcones Catalyzed by Chiral Phosphoric Acids
作者:Arrigo Scettri、Rosaria Villano、Maria Acocella
DOI:10.3390/molecules14083030
日期:——
The reaction of indole with chalcones, to give Michael-type adducts, was found to occur with good efficiency (up to 98% yield) and moderate enantioselectivity (up to 52% e.e.) in the presence of a chiral BINOL-based phosphoricacid. Furthermore, the alkylation products can be obtained in much higher e.e.s after one only crystallization.
发现吲哚与查耳酮反应生成迈克尔型加合物,在手性 BINOL 型磷酸存在下以良好的效率(高达 98% 的产率)和中等的对映选择性(高达 52% ee)发生。此外,仅在一次结晶后可以以更高的 ee 获得烷基化产物。
Highly Enantioselective Synthesis of β-Heteroaryl-Substituted Dihydrochalcones Through Friedel-Crafts Alkylation of Indoles and Pyrrole
A highly enantioselective Friedel–Crafts (F–C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N′‐dioxide–Sc(OTf)3 complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85–92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading