Titanium-mediated rearrangement of cyclopropenylmethyl acetates to (E)-halodienes
作者:Gary Gallego、Alireza Ariafard、Kiet Tran、David Sandoval、Leera Choi、Yi-Hsun Chen、Brian F. Yates、Fu-Ming Tao、Christopher J. T. Hyland
DOI:10.1039/c0ob01046d
日期:——
TiCl4 and TiBr4 rapidly transform cyclopropenylmethyl acetates to (E)-halodienes via ring-opening to allyl-vinyl cations. DFT calculations suggest that the regioselectivity of the halogenation of this cationic intermediate by [TiX4OAc]− is under thermodynamic control, while the stereoselectivity is governed by kinetics.
TiCl4 和 TiBr4 通过烯丙基乙烯阳离子的开环作用迅速将环丙烯甲基乙酸酯转化为 (E)- 卤代二烯。DFT 计算表明,[TiX4OAc]- 卤化这种阳离子中间体的区域选择性受热力学控制,而立体选择性则受动力学控制。