Unsymmetrical 1,1-diborated multisubstituted sp<sup>3</sup>-carbons formed via a metal-free concerted-asynchronous mechanism
作者:Ana B. Cuenca、Jessica Cid、Diego García-López、Jorge J. Carbó、Elena Fernández
DOI:10.1039/c5ob01523e
日期:——
unsymmetrical 1,1-diboration of diazo compounds, formed in situ from aldehydes and cyclic and non-cyclic ketones, in the absence of any transition metal complex. The heterolytic cleavage of the mixed diboron reagent, Bpin–Bdan, and the formation of two geminal C–Bpin and C–Bdan bonds has been rationalised based on DFT calculations to occur via a concerted-asynchronous mechanism. Diastereoselection is attained
我们已经通过实验证明了在没有任何过渡金属络合物的情况下,由醛,环状和非环状酮原位形成的重氮化合物的不对称1,1-二硼化反应。混合双硼试剂Bpin–Bdan的异源裂解,以及两个双键C–Bpin和C–Bdan键的形成已根据DFT计算合理化,并通过协调异步机制进行。在取代的环己酮上实现了非对映选择,DFT研究提供了对选择性起源的理解。从多取代的sp 3-碳进行的Bpin的醇盐辅助的选择性脱硼和Bdan稳定的碳负离子的产生容易进行选择性的原脱硼序列。