Regioselectivity in the Cu(I)-Catalyzed [4 + 2]-Cycloaddition of 2-Nitrosopyridine with Unsymmetrical Dienes
作者:Anh T. Tran、Peng Liu、K. N. Houk、Kenneth M. Nicholas
DOI:10.1021/jo5005907
日期:2014.6.20
prox/dist product regioselectivity produced by the corresponding catalysts. Transition states in the Cu(CH3CN)4+- and Cu(diimine)2+-catalyzed reactions are located that account for the observed regioselectivities. Coordination effects on the regioselectivity are derived from FMO orbital interactions and the extent of electron transfer between the Cu center and the coordinated nitroso and diene units.
2- nitrosopyridine(PyrNO)与二烯1,3-戊二烯,热(非催化)和Cu(I)催化的反应ê,ë -2,4 - hexadienol,1- phenylbutadiene进行了实验和计算研究。前两个二烯的未催化反应以低区域选择性发生,而后者以完全的近端选择性进行。使用M06 / 6-311 + G(d,p)-SDD方法,计算了2-亚硝基吡啶与(E)-1,3-戊二烯和1-苯基丁二烯反应的各种一致的过渡态。与实验结果定量吻合,(a)在最稳定的过渡态(内向抗-内向)之间未发现能量差(0.0 kcal / mol)和内切DIST抗,在戊二烯/ PyrNO反应,导致几乎等量的PROX和DIST cycloadducts,和(b)的近端过渡状态中强烈建议(3.7千卡/摩尔)的远端的高度选择性苯基丁二烯/ PyrNO反应。Cu(CH 3 CN)4 +催化时,戊二烯/ PyrNO反应的区域选择性显着提高(90:10