Rhodium-Catalyzed Remote C-8 Alkylation of Quinolines with Activated and Unactivated Olefins: Mechanistic Study and Total Synthesis of EP4 Agonist
作者:Ritika Sharma、Inder Kumar、Rakesh Kumar、Upendra Sharma
DOI:10.1002/adsc.201700542
日期:2017.9.4
rhodium(III)‐catalyzed regioselective distal C(sp2)‐H bond alkylation of quinoline N‐oxides using olefins as alkyl source and N‐oxide as the traceless directing group. The reaction exhibits broad substrate scope with excellent selectivity for C‐8 position and good yields of alkylated products. The usefulness of the developed catalytic protocol is established by synthesis of EP4 agonist. In mechanistic study, C‐8 olefinated
本文报道的是铑(III)催化的区域选择性远侧C(SP 2)-H键的喹啉烷基化ñ -oxides使用烯烃作为烷基源和Ñ氧化物作为无痕引导组。该反应具有广泛的底物范围,对C-8位置具有出色的选择性,并且烷基化产物的收率高。通过合成EP4激动剂可以确定已开发的催化方案的实用性。在机理研究中,C-8烯烃化喹啉被确定为反应中间体,在存在铑(I)物种(反应过程中由铑(III)生成)和甲酸的情况下,该中间体还原为所需的C-8烷基化产物。在四氟硼酸银的存在下,由二甲基甲酰胺生产甲酸。