Cobalt Catalysis: C7 Alkynylation of Indolines with a Bromoalkyne

Abstract

A method for the cobalt-catalyzed C-7 alkynylation of indolines with (bromoethynyl)triisopropylsilane under mild conditions is described, leading to a diverse range of alkynylated indolines in good to excellent yields. Kinetic isotope studies indicate that the formation of a cobaltacycle might be the turnover-limiting step. Additionally, a gram-scale synthesis and oxidation of an indoline to an indole have been carried out successfully with excellent yields.

Key words

cobalt - indolines - bromoalkyne - C–H activation - alkynylation

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