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Herein, we report the first example of enantioselective (2+1) cycloaddition of thioketones with α‐diazo pyrazoleamides for the direct synthesis of tetrasubstituted thiiranes. In the presence of chiral N,N′‐dioxide/cobalt(ΙΙ) complexes (2–5 mol%), excellent efficiency (up to 99 % yield within 15 mins) and high stereoselectivity (up to >19 : 1 dr and 97 % ee) are available. Elaborations of thiiranes via desulfuration have also been conducted to deliver tetrasubstituted olefins. Density functional theory calculations reveal that the reaction initiates from a doublet state cobalt(ΙΙ) carbenoid, which is followed by a quartet cobalt(ΙΙ)‐bound thiocarbonyl ylide pathway. This work provides a route for the selective construction of tetrasubstituted thiiranes and olefins that are otherwise difficult to access. [ABSTRACT FROM AUTHOR]

Carbenes, Cobalt(II)/N,N'-Dioxide, Thiiranes, Thioketones, -Diazo Compounds Keywords: Carbenes; Cobalt(II)/N,N'-Dioxide; Thiiranes; Thioketones; -Diazo Compounds EN Carbenes Cobalt(II)/N,N'-Dioxide Thiiranes Thioketones -Diazo Compounds 1 1 1 04/27/22 20220502 NES 220502 B Asymmetric Catalysis b Tetrasubstituted thiiranes can be synthesized by an asymmetric catalytic (2+1) cycloaddition of thioketones as reported by Xiaohua Liu, Yun-Dong Wu, Xiaoming Feng et al. in their Research Article (e202201151). [Extracted from the article]