demonstrated that formamides reacted faster than enals, which reacted faster than enoates; saturated aldehydes did not undergo insertion. With a cis-disubstituted silacyclopropane, products of silylene transfer were observed. The stereochemistry, regiochemistry, and chemoselectivity of carbonyl insertion as well as the silylene transfer processes can be explained by a mechanism involving transmetalation
硅环丙烷与羰基化合物在温和条件下(10 mol%
金属盐,e22 °C)以立体定向和高度立体选择性、区域选择性和
化学选择性的方式反应。在大多数情况下,CuI 或 CuBr2 是最佳催化剂,尽管 ZnBr2 在一些例子中表现得相当好。插入发生时保留构型,并且在 enal 和甲酰胺的情况下,在新形成的立体中心具有高非对映选择性。对于不对称底物,插入发生在具有完全区域选择性的更多取代的碳-
硅键上。竞争实验表明,甲酰胺反应比 enal 快,而 enal 反应比 enoate 快;饱和醛没有进行插入。对于顺式二取代的
硅杂
环丙烷,观察到亚甲
硅烷基转移产物。立体
化学,