The carbon-to-silicon switch gives rise to silacycles that offer eminent biological and photophysical properties. Access to chiral silacycles, especially midsized ones, via intermolecular coupling remains a considerable challenge due to limited synthetic methods. Herein, rhodium(I)-catalyzed annulations between benzosilacyclobutenes (SCBs) and bicyclic olefins are presented. A series of stable seven-membered chiral silacycles have been accessed in high enantioselectivity via the enantioselective [4 + 3] annulation between SCBs and 7-oxabenzonorbornadienes via a formal [2σ + 2σ] C–C and O–Si coupling. The mechanism of the enantioselective [4 + 3] annulation between SCBs and 7-oxabenzonorbornadienes has been investigated, where C–Si oxidative addition of the SCB has been established as the turnover-limiting step.

中文翻译：

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铑催化（不对称）硅环丁烷与双环烯烃的环化，通过 C-Si 键活化


碳硅转换产生了具有突出生物和光物理特性的硅环。由于合成方法有限，通过分子间偶联获得手性硅烷环，尤其是中型硅烷环仍然是一个相当大的挑战。在此，提出了苯并硅环丁烯 （SCB） 和双环烯烃之间的铑 （I） 催化环化。通过 SCB 和 7-恶杂苯并硼二烯之间的对映选择性 [4 + 3] 环化，通过正式的 [2σ + 2σ] C-C 和 O-Si 偶联，以高对映选择性获得一系列稳定的七元手性硅烷环。已经研究了 SCB 和 7-恶杂苯并硼二烯之间的对映选择性 [4 + 3] 环化机制，其中 SCB 的 C-Si 氧化加成已被确定为周转限制步骤。