Iron-catalyzed radical aryldifluoromethylation of activated alkenes to difluoromethylated oxindoles

Abstract

An iron-catalyzed aryldifluoromethylation of activated alkenes under mild reaction conditions has been developed, which is a rare example where a cosolvent is used to improve the reaction yield along with Fenton's reagent and thus provides an economic and green method for the synthesis of a variety of difluoromethylated oxindoles. Preliminary mechanistic investigations indicate a radical addition path.

Iron Catalysis in Organic Synthesis

“…707 This transformation provides difluoromethylated oxindoles in high yields and under mild reaction conditions (DMF/THF, 60°C).…”

Mechanistic investigation on radical-induced construction of oxindoles: radical versus electrophilic cyclization

“…Although this mechanism could be accepted widely, [23][24][25][26][27][28][29][30][31][32][33][34] some critical issues deserve to take into account. In particular, several details of the reaction mechanism need to be claried.…”

Iron‐Promoted Radical Reactions: Current Status and Perspectives

“…By using H 2 O 2 as an oxidant in DMSO/THF,W ang et al reported the iron-catalyzed preparation of CF 2 SO 2 Ph-substituted oxindoles. [30] Again, decomposition of H 2 O 2 by Fe II initiated the An interesting, convergent radical cyclization of an aldehyde with two alkene substituents was reported by Li andc o-workers. [31] Thisn ew method allowed the preparation of polyfunctionalized 3,4-dihydropyrans by using FeCl 2 as ac atalysta nd di-tert-butylperoxide as an oxidant.…”