Photoinduced Five‐Component Radical Relay Aminocarbonylation of Alkenes

Abstract

Radical single carbonylation reactions with CO constitute a direct and robust strategy toward various carbonyl compounds from readily available chemicals, and have been extensively studied over the past decades. However, realizing highly selective catalytic systems for controlled double radical carbonylation reactions has remained a substantial challenge, particularly for the more advanced multi‐component variants, despite their great potential value. Herein, we report a visible light‐driven radical relayed five‐component radical double aminocarbonylation reaction of unactivated alkenes using CO under metal‐free conditions. This protocol provides direct access to valuable γ‐trifluoromethyl α‐ketoamides with good yields and high selectivity. Crucial was the identification of distinct dual roles of amine coupling partners, sequentially acting as electron donors for the formation of photoactive electron donor‐acceptor (EDA) complexes with radical precursors and then as a CO acceptor via nitrogen radical cations to form carbamoyl radicals. Cross‐coupling of carbamoyl radicals with the acyl radicals that are formed in an alkene‐based relay process affords double aminocarbonylation products.

Copper-Catalyzed Radical Relay 1,3-Carbocarbonylation across Two Distinct C═C Bonds

“…The radical relay reactions commonly involve three pivotal stages: radical formation, radical migration, and radical rebound . Given its functions of intermolecular assembly, complex bond construction, and functionalization across distal bonds, this strategy enables the rapid construction of complex molecules, and thus obtains extensive attention in synthetic chemistry . In particular, the radical relay method starts with the breakage of C(sp 3 )–X (X = Br, I), N–H, and N–O bonds to generate initial radicals followed by cyclization to the intramolecular CC bonds to form a new carbon radical intermediate, which further reacts with another CC bond.…”