Directing the regioselectivity of rhodium(I) catalysed cyclisation of 2-alkynyl benzoic acids
作者:Bradley Y.-W. Man、Astrid Knuhtsen、Michael J. Page、Barbara A. Messerle
DOI:10.1016/j.poly.2013.06.010
日期:2013.9
Rhodium(I) dicarbonyl complexes 1–4 containing chelating N-donor ligands bis(pyrazolyl)methane (bpm), bis(imidazolyl)methane (bim), tris(pyrazolyl)toluidine (tpt) or tris(imidazolyl)methanol (tim) were investigated as catalysts for the hydroalkoxylation of alkynyl benzoic acids (5a–g). The regioselectivity of the reaction was shown to be highly dependent on the nature of the terminal alkyne substituent
铑(I)二羰基配合物1 - 4含螯合剂的N-供体配体双(吡唑基)甲烷(BPM),双(咪唑基)甲烷(BIM),三(吡唑基)甲苯胺(TPT)或三(咪唑基)甲醇(TIM)被研究为炔基苯甲酸(5a – g)的加氢烷氧基化的催化剂。已显示反应的区域选择性高度依赖于炔醇底物的末端炔基取代基(R)的性质。还确定了配合物3和4中存在第三个未配位的N供体基团会抑制这些配合物的催化效率,并且确定形成任一内环的反应的选择性(6)或外环(7)的氢烷氧基化产物受配合物4中存在的侧羟基的影响。我们使用13 C NMR光谱法来量化炔基苯甲酸CC键的极性,并讨论了将这种键极性测量值与反应的区域选择性相关联的努力。