Activation of Diboron Reagents with Brønsted Bases and Alcohols: An Experimental and Theoretical Perspective of the Organocatalytic Boron Conjugate Addition Reaction
作者:Cristina Pubill-Ulldemolins、Amadeu Bonet、Carles Bo、Henrik Gulyás、Elena Fernández
DOI:10.1002/chem.201102209
日期:2012.1.23
Bases play an important role in organocatalytic boron conjugate addition reactions. The sole use of MeOH and a base can efficiently transform acyclic and cyclic activated olefins into the corresponding β‐borated products in the presence of diboron reagents. Inorganic and organic bases deprotonate MeOH in the presence of diboron reagents. It is concluded, on the basis of theoretical calculations, NMR
碱在有机催化硼共轭物加成反应中起重要作用。在二硼试剂存在下,仅使用MeOH和碱可以有效地将无环和环状活化烯烃转化为相应的β-硼酸酯产物。在二硼试剂存在下,无机碱和有机碱使MeOH去质子化。根据理论计算,NMR光谱数据和ESI-MS实验得出的结论是,甲醇盐阴离子与二硼试剂形成路易斯酸碱加合物。SP 2甲醇-二硼加合物的B原子具有很强的亲核特性,并且会侵蚀电子不足的烯烃。甲醇使中间体质子化,生成产物和另一种甲醇根阴离子。这似乎是激活二硼试剂并使其适合掺入目标有机分子的最简单方法。