Synthesis of Terminal Alkenylindolines via Rhodium‐Catalyzed Direct CH Alkenylation With Alkenyl Borates

ABSTRACT An efficient method for the synthesis of valuable terminal C7‐alkenylated indolines through the direct C–H alkenylation of N ‐pyridinyl indolines in the presence of a rhodium catalyst has been developed. Alkenyl borates were first used as a useful alkenyl reagent for C–H functionalization of indolines. Under mild reaction conditions, a series of indolines with different functional groups were compatible in this transformation, affording the C7‐alkenylated product in good to excellent yields. Moreover, the C7‐alkenylated indoline can be conveniently converted to the pyrroloquinoline derivative, which is a popular tricyclic indoline skeleton in bioactive compounds, highlighting its potential application value.