Diastereoselective Synthesis of Thieno[3′,2′:4,5]cyclopenta[1,2-<i>d</i>][1,3]oxazolines − New Ligands for the Copper-Catalyzed Asymmetric Conjugate Addition of Diethylzinc to Enones
作者:Bianca Flavia Bonini、Elena Capitò、Mauro Comes-Franchini、Alfredo Ricci、Andrea Bottoni、Fernando Bernardi、Gian Pietro Miscione、Laurent Giordano、Andrew R. Cowley
DOI:10.1002/ejoc.200400351
日期:2004.11
Several new ligands featuring a rigid three ring skeleton have been prepared for the first time following a modular approach. Chirality has been introduced by use of an oxazoline moiety fused with a cyclopenta[b]thiophene backbone. The efficiency and stereochemical impact of these ligands on the copper-catalyzed enantioselective addition of Et2Zn to chalcone was examined and enantiomeric excesses up
采用模块化方法首次制备了几种具有刚性三环骨架的新配体。通过使用与环戊二烯[b]噻吩骨架稠合的恶唑啉部分引入了手性。研究了这些配体对铜催化的 Et2Zn 对映选择性加成到查耳酮的效率和立体化学影响,使用在环戊二烯部分被甲基取代的配体 (R,R)-16 实现了高达 79% 的对映体过量。计算和 ESI 质谱研究表明,这些新化合物表现为 Cu+ 的单齿配体。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)