This work reports gold‐catalyzed [3+2]‐annulations of α‐diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3‐dihydrofurans with high regio‐ and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]‐annulations with α‐diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral forms of gold and phosphoric acid. Our mechanistic analysis supports that cyclopentadienes serve as nucleophiles to attack gold carbenes at the more substituted alkenes, yielding gold enolates that complex with chiral phosphoric acid to enhance the enantioselectivity.

中文翻译：

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金催化的带有环戊二烯四取代烯烃的α-芳基重氮酮[3 + 2]环糊精：高立体选择性和对映选择性

这项工作报道了用高取代的环戊二烯进行金催化的α-重氮酮的[3 + 2]环化反应，从而提供具有高区域和立体选择性的双环2,3-二氢呋喃。该反应突出表明四取代烯烃首次成功经历了与α-重氮羰基的[3 + 2]环化反应。使用金和磷酸的手性形式，还以高对映选择性实现对映选择性环化。我们的机理分析支持环戊二烯充当亲核试剂，以攻击更多取代的烯烃上的金卡宾，产生与手性磷酸络合的烯醇金，以增强对映选择性。