Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
Current address: Department of Chemistry, Western Kentucky University, Bowling Green, KY, 42101, USA.
Angew Chem Int Ed Engl. 2018 Aug 6;57(32):10343-10346. doi: 10.1002/anie.201805323. Epub 2018 Jul 9.
Enoldiazoimides, a new subclass of enoldiazo compounds, generate enol-substituted carbonyl ylides whose reactions with sulfur ylides enable an unprecedented formal [4+2] cycloaddition. The resulting multifunctionalized indolizidinones, which incorporate sulfur, are formed in good yields under mild reaction conditions. The uniqueness of this transformation stems from the role of the silyl-protected enol, since the corresponding acetyldiazoimide failed to provide any cross-products in metal-catalyzed reactions with sulfur ylides. This copper-catalyzed cycloaddition is initiated with the generation of enol-substituted carbonyl ylides and sulfur ylides from enoldiazoimides and sulfonium salts, respectively, and proceeds through stepwise six-membered ring formation, C-O and C-S bond cleavage, and silyl and acetyl group migration.
Enoldiazoimides 是 enoldiazo 化合物的一个新子类，可生成烯醇取代的羰基叶立德，其与硫叶立德的反应可实现前所未有的形式 [4+2]环加成。在温和的反应条件下，以良好的收率形成了包含硫的多功能化吲哚利定酮。这种转化的独特之处源于硅保护烯醇的作用，因为相应的乙酰基二氮杂异吲哚在与硫叶立德的金属催化反应中未能提供任何交叉产物。该铜催化环加成是通过分别从 enoldiazoimides 和鏻盐中生成烯醇取代的羰基叶立德和硫叶立德引发的，并且通过逐步的六元环形成、C-O 和 C-S 键断裂以及硅烷基和乙酰基迁移进行。
