AgI-Promoted Cascade for Difluoromethylation of Activated Alkenes to Difluoromethylated Oxindoles.

A simple Ag^I-mediated direct difluoromethylation reaction of activated alkenes by using TMSCF₂COOEt (TMS = trimethylsilyl) under mild reaction conditions has been described. This reaction tolerates a variety of functional groups and allows for a highly efficient synthesis of various difluoro-containing oxindoles. Mechanistic investigations indicate that a difluoromethyl radical initiated the cascade sequence by undergoing an addition reaction to the alkene. [ABSTRACT FROM AUTHOR]