The synthesis of structurally diverse silacycles is crucial for the silicon-containing drug and agrochemical development. However, catalytic synthesis of dense-functionalized silacycles that based on selectively cleavage and reconstruction of the carbon–silicon bond in the organosilicon precursors remain largely elusive. Herein we report a divergent catalysis of ring-reconstruction transformation of silacycles based on rhodium-promoted Si-C bond cleavage whereby the cyclic silylmetal intermediates undergo a highly efficient and novel intramolecular Si-C bond-forming reactions under mild conditions. Under the ligand-controlled Rh-catalyzed intramolecular silacyclization, two different pathways of new Si-C bond -forming transformations were established through intramolecular sila-cyclization reaction between alkyne moieties and silacyclobutane moieties, resulting into structurally diverse chromane-like silacycles. Furthermore, the DFT calculations supported that bulky P-ligand P5 and the TADDOL-derived phosphonite ligand L1 played different roles to control the pathway in Rh-catalyzed intramolecular silacyclization and subsequent olefin migration process.

中文翻译：

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配体控制的 Rh（I） 催化的分子内炔烃 Sila 环化：发散催化和机理研究


结构多样的硅烷环的合成对于含硅药物和农用化学品的开发至关重要。然而，基于有机硅前驱体中碳硅键的选择性裂解和重建的致密官能化硅环的催化合成在很大程度上仍然难以捉摸。在此，我们报道了基于铑促进的 Si-C 键裂解的硅烷环重构转化的不同催化，其中环状硅烷金属中间体在温和条件下发生高效和新颖的分子内 Si-C 键形成反应。在配体控制的 Rh 催化的分子内硅烷环化下，通过炔烃部分和硅环丁烷部分之间的分子内硅烷环化反应建立了两种不同的新 Si-C 键形成转变途径，从而产生结构不同的色质样硅烷环。此外，DFT 计算支持大体积 P 配体 P5 和 TADDOL 衍生的膦酸盐配体 L1 在控制 Rh 催化的分子内甲烷环化和随后的烯烃迁移过程中发挥不同的作用。