Stereoselective Synthesis of Alkenyl Silanes, Sulfones, Phosphine Oxides, and Nitroolefins by Radical C–S Bond Cleavage of Arylalkenyl Sulfides

Abstract

A radical-mediated approach has been introduced for the C-S bond activation of arylalkenyl sulfides. The protocol provides an efficient approach for the generation of various alkenes including alkenyl silanes, sulfones, phosphine oxides, and nitroolefins. In most cases, these radical substitutions are performed under metal-free conditions with stereospecificity.

S−H⋅⋅⋅π Driven Anti‐Markovnikov Thiol‐Yne Click Reaction

“…Similarly the (2‐phenylethane‐1,1‐diyl)bis(phenylsulfane) 9 was synthesized in 93% yield from 3 aa using perchloric acid and thiophenol ( 2 a ) . A brief literature survey is shown in Figure b towards the use of styryl( p ‐tolyl)sulfane 10 for the synthesis of 11 and 12 . The gram scale synthesis of 3 aa (isolated, 2.2 g) was performed under neat condition and the product was isolated in 95% yield (Figure c).…”

“…(4‐Nitrophenyl)(styryl)sulfane (3 ai) : E : Z ratio 53 : 47, R f =0.5 (5% ethyl acetate/hexane); Yellow solid; yield 96% (136 mg); mp 82–85 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 8.25–8.11 (m, 2H), 7.59–7.28 (m, 7H), 7.03 (d, J =15.4 Hz, 1H, major), 6.89 (m, 1H, major), 6.85 (m, 1H, minor), 6.52 (d, J =10.4 Hz, 1H, minor); 13 C NMR (100 MHz, CDCl 3 ) δ 146.6, 146.2, 145.9, 145.8, 138.1, 135.7, 135.6, 132.2, 129.1, 129.0, 128.9, 128.6, 128.1, 128.0, 127.1, 126.7, 124.3, 124.2, 120.7, 118.3.…”

The Chemistry of Peresters

“…Generation of a silyl radical (Figure 10b) is also the basis for stereoselective synthesis of E ‐alkenylsilanes from vinyl sulfides. The requirement for stoichiometric initiator presumably reflects the efficiency of chain termination via dimerization of the released thiyl radical . The mechanism is shown in Figure .…”

Recent Advances in Reactions of Heteroatom-Centered Radicals

“…In 2017, the desulfurizative radical silylation of arylalkenyl sulfides was reported using similar conditions. 84 A similar catalytic reaction was applicable to cascade reactions. In 2017, Li and co-workers reported the synthesis of silylated spiro systems by iron-catalyzed radical reactions (Scheme 47).…”