Design of New Chiral Phase-Transfer Catalysts with Dual Functions for Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones
作者:Takashi Ooi、Daisuke Ohara、Masazumi Tamura、Keiji Maruoka
DOI:10.1021/ja048600b
日期:2004.6.1
has been designed as a promising, dual-functioning catalyst for the highly enantioselective epoxidation of α,β-unsaturated ketones under mild phase-transfer conditions. For instance, vigorous stirring of a mixture of chalcone, 1-Br (3 mol %), and 13% NaOCl in toluene at 0 °C for 24 h gave rise to epoxy chalcone quantitatively with 96% ee. A variety of α,β-unsaturated ketones can also be epoxidized with
一种具有二芳基甲醇官能团作为底物识别位点的新型手性溴化铵 1-Br 已被设计为一种有前途的双功能催化剂,用于在温和的相转移条件下对 α,β-不饱和酮进行高度对映选择性环氧化。例如,将查耳酮、1-Br (3 mol%) 和 13% NaOCl 在甲苯中的混合物在 0°C 下剧烈搅拌 24 小时,可定量生成 96% ee 的环氧查耳酮。各种 α,β-不饱和酮也可以通过严格的立体化学控制进行环氧化,清楚地证明了本系统的有效性和实用性。此外,1-PF6 的成功单晶 X 射线衍射分析揭示了其独特的三维分子结构,并为假设过渡态提供了有用的信息。