A Valuable, Inexpensive CuI/N-Heterocyclic Carbene Catalyst for the Selective Diboration of Styrene
作者:Vanesa Lillo、Manuel R. Fructos、Jesús Ramírez、Ataualpa A. C. Braga、Feliu Maseras、M. Mar Díaz-Requejo、Pedro J. Pérez、Elena Fernández
DOI:10.1002/chem.200601146
日期:2007.3.16
The complexes [Cu(NHC)(NCMe)]BF4 (NHC=N-heterocyclic ligand), with bis(catecholato)diboron (B2(cat)2) as the boron source, efficiently catalyze the diboration of styrene with very high degrees of conversion. With the appropriate NHC ligand, the reaction proceeds quantitatively toward the diborated derivative PhCH(Bcat)--CH2(Bcat). The [styrene]/[B2(cat)2] ratio also has a strong effect on the selectivity:
以双(邻苯二甲酰基)二硼(B2(cat)2)为硼源的配合物[Cu(NHC)(NCMe)] BF4(NHC = N-杂环配体),可高效催化苯乙烯的二硼酸酯化反应。转换。使用适当的NHC配体,反应可定量地朝二硼酸酯衍生物PhCH(Bcat)-CH2(Bcat)进行。[苯乙烯] / [B2(cat)2]的比率也对选择性有很大影响:使用过量的苯乙烯可以改变选择性,从而仅形成单硼酸酯衍生物PhCH2--CH2(Bcat) 。DFT计算表明,在铜上没有发生氧化加成过程,但是催化环中涉及包含配位的σ键的中间体。