Three-Component Carbosilylation of Alkenes by Merging Iron and Visible-Light Photocatalysis

Abstract

A mild, efficient, and one-pot protocol for three-component carbosilylation of alkenes with imidazoheterocycle and silanes has been developed by merging iron­(II) and visible-light photocatalysis. This C–C and C–Si bond-forming method provides functionalized organosilicon derivatives having imidazoheterocycles moieties in good yields. The reaction possibly proceeds through a radical pathway.

Recent Advances in Non-Precious Metal Catalysis

“…92 The methodology requires both Fe and visible-light photocatalysis. 93 Screening of solvents, photocatalysts, and additives for optimized carbosilylation of the three components styrene, (TMS) 3 SiH, and 8-methyl-2-phenylimidazo[1,2-α]pyridine resulted in optimal conditions demonstrated on a large variety of imidazopyridines, imidazothiazoles, and benzoimidazothiazoles in good yields (Scheme 45). The reaction was compatible with a large variety of substituents on both the pyridine ring of imidazo[1,2-α]pyridine and the phenyl ring.…”

“…The effective three-component carbosilylation of alkenes using Fe catalysis for the synthesis of silicon analogs of imidazoheterocycles was reported by Hajra and co-workers . The methodology requires both Fe and visible-light photocatalysis . Screening of solvents, photocatalysts, and additives for optimized carbosilylation of the three components styrene, (TMS) 3 SiH, and 8-methyl-2-phenylimidazo­[1,2-α]­pyridine resulted in optimal conditions demonstrated on a large variety of imidazopyridines, imidazothiazoles, and benzoimidazo­thiazoles in good yields (Scheme ).…”

Recent Developments in the Photochemical Synthesis of Functionalized Imidazopyridines

“…The Hajra group deepened the concept of C–H alkylation by exploring the three-component carbosilylation of alkenes in the imidazopyridine scaffold [ 54 ]. The combination of a metal catalyst (FeCl 2 ) and blue-LED photocatalysis enabled the C–C and C–Si bond formation.…”

Light-Promoted Arylsilylation of Alkenes with Hydrosilanes

“…Of note, recently, state-of-the-art metallophotoredox catalysis offers an elegant way to achieve 1,2-arylsilylation of alkene using readily available hydrosilanes as the silicon source, but fewer examples were reported , in comparison to the approaches under thermal conditions, which probably ascribed to competing reactions of hydrosilylation of alkenes. , Hu and co-workers reported first metallophotoredox catalysis for arylsilylation of electron-deficient alkenes, where the expensive Ir-based photocatalyst and air-sensitive Ni­(COD) 2 were required . The other metallophotoredox catalysis was developed by Hajira and co-workers; however, excess oxidants are required as well . In addition, among them, only tris­(trimethylsilyl)­silane [(TMS) 3 SiH] can be used as the silane source , (Figure a).…”

“…The other metallophotoredox catalysis was developed by Hajira and co-workers; however, excess oxidants are required as well . In addition, among them, only tris­(trimethylsilyl)­silane [(TMS) 3 SiH] can be used as the silane source , (Figure a). To our best knowledge, a β-silyl alkyl cation, β-silyl alkyl anion, or metal complex for the generation of carbosilylation products via photocatalysis has been reported.…”