As a class of readily available and multifunctional building blocks, the chemistry of 4-alken-2-ynyl carbonates remains to be explored. Presented herein is a palladium-catalysed cascade transformative reaction between 4-alken-2-ynyl carbonates and ortho-functionalised activated alkenes. Achiral 1,1-bisalkyl-4-alken-2-ynyl carbonates undergo highly regioselective propargylic substitution with ortho-hydroxyphenyl-tethered activated alkenes, and an auto-tandem vinylogous addition, unusual central carbon Tsuji-Trost alkylation, protonation and β-H elimination process is followed to furnish fused and spirocyclic frameworks with high structural complexity. Even kinetic transformations with racemic 1-monoalkylated 4-alken-2-ynyl carbonates can be well accomplished in the assemblies with ortho-aminophenyl-tethered activated alkenes, affording the analogous alkaloid architectures. This palladium-catalysed auto-tandem protocol exhibits excellent chemo-, regio-, stereoselectivity and reaction efficacy, and substantial functionality compatibility is also observed.

中文翻译：

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钯催化的 4-烯基-2-炔基碳酸酯的不对称级联转化以构建复杂框架


作为一类现成的多功能结构单元，4-烯烃-2-炔基碳酸酯的化学性质仍有待探索。本文介绍的是 4-烯烃-2-炔基碳酸酯和邻位官能化活化烯烃之间的钯催化级联转化反应。非手性 1,1-双烷基-4-烯烃-2-炔基碳酸酯经历邻位羟基苯基拴系活性烯烃的高区域选择性炔丙基取代，并遵循自动串联乙烯基添加、不寻常的中心碳 Tsuji-Trost 烷基化、质子化和 β-H 消除过程，以提供具有高结构复杂性的熔融和螺环框架。即使是外消旋 1-单烷基化 4-烯基-2-炔基碳酸酯的动力学转化也可以在邻氨基苯基拴系活化烯烃的组装体中很好地完成，从而提供类似的生物碱结构。这种钯催化的自动串联方案表现出优异的化学、区域、立体选择性和反应功效，并且还观察到实质性的功能兼容性。