Herein, we present a palladium-catalyzed tandem [4+1] cyclo­addition of 4-vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-ones with ­N-tosyl­hydrazones. The reaction is accomplished by merging the in situ generated aza-ortho-quinone methides (aza-o-QMs) with nucleophilic carbenes. This method enables the construction of diverse indolines with broad functional group compatibility in good yields with high levels of diastereoselectivity under mild conditions.

中文翻译：

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非对映选择性钯催化的 [4+1] 4-Vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-ones 与原位形成的卡宾的环加成反应

在此，我们提出了 4-vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-ones 与 N-tosylhydrazones 的钯催化串联 [4+1] 环加成反应。该反应是通过将原位生成的氮杂邻醌甲基化物 (aza-o-QMs) 与亲核卡宾合并来完成的。该方法能够在温和条件下以良好的收率和高水平的非对映选择性构建具有广泛官能团兼容性的多种二氢吲哚。