Cyclometalated Chiral-at-Ruthenium Catalyst for Enantioselective Ring-Closing C(sp<sup>3</sup>)–H Carbene Insertion to Access Chiral Flavanones
作者:Feng Han、Peter H. Choi、Chen-Xi Ye、Yvonne Grell、Xiulan Xie、Sergei I. Ivlev、Shuming Chen、Eric Meggers
DOI:10.1021/acscatal.2c02423
日期:2022.8.19
A competing oxygen attack pathway involving the formation and [1,2]-shift (Stevens rearrangement) of an oxonium ylide intermediate was successfully suppressed in favor of a catalytic enantioselective ring-closing C(sp3)–H carbene insertion. Density functional theory calculations provide a rationale for the observed C–H insertion over the undesirable C–O formation pathway. The method provides access
具有完全以金属为中心的手性的环金属化钌配合物催化重氮酮转化为手性黄烷酮,产率高达 99%,ee 高达 96%。涉及氧鎓叶立德中间体的形成和[1,2]-移位(史蒂文斯重排)的竞争性氧攻击途径被成功抑制,有利于催化对映选择性闭环C(sp 3)-H卡宾插入。密度泛函理论计算为在不希望的 C-O 形成途径上观察到的 C-H 插入提供了基本原理。该方法提供了获得各种手性黄烷酮的途径,这些黄烷酮被认为是具有多种生物活性的特殊支架。