Sterically Controlled Ru(II)-Catalyzed Divergent Synthesis of 2-Methylindoles and Indolines through a C–H Allylation/Cyclization Cascade
作者:Manash Kumar Manna、Gurupada Bairy、Ranjan Jana
DOI:10.1021/acs.joc.8b01034
日期:2018.8.3
A ruthenium-catalyzed synthesis of 2-methylindole was accomplished via a C–H allylation/oxidative cyclization cascade. Strategically, β-hydride elimination from the σ-alkyl-Ru intermediate has been suppressed by steric hindrance from a remote position. Hence, 2-methylindolines from the corresponding ortho-substituted anilines were achieved via protodemetalation in lieu of β-hydride elimination under
钌催化的2-甲基吲哚的合成是通过C–H烯丙基化/氧化环化级联反应完成的。从策略上讲,较远位置的空间位阻已抑制了从σ-烷基-Ru中间体中除去β-氢化物。因此,在改性反应条件下,通过原金属脱金属代替β-氢化物消除,从相应的邻位取代苯胺获得了2-甲基二氢吲哚。这种温和的分子间环化级联反应可通过氧化还原中性钌催化剂平稳进行,而无需化学计量的金属氧化剂,例如银(I)或铜(II)盐,可提供出色的官能团耐受性。