Palladium-catalyzed intramolecular enantioselective C(sp(3))–H insertion of donor/donor carbenes

Herein, the first palladium-catalyzed intramolecular enantioselective C(sp(3))–H insertion reaction of donor–donor carbenes has been successfully achieved. This facile protocol enables the rapid construction of a collection of enantioenriched decorated indolines with two contiguous stereocenters in a single step. Both enynones and diazo compounds are efficient donor–donor carbene precursors for this reaction. By an adjustment of ligands and protecting groups of the substrates, the palladium–carbene intermediates from diazo compounds afford sparse trans-indolines with excellent enantioselectivities, while carbenes from enynones deliver cis-indolines exclusively. Based on the control reactions and Hammett analysis, a stepwise Mannich-type pathway through a short-lived and compact zwitterionic intermediate is proposed.