Generation of 1,2-Bisketenes from Cyclobutene-1,2-diones by Flash Photolysis and Ring Closure Kinetics<sup>1</sup><sup>a</sup>
作者:Annette D. Allen、Jim D. Colomvakos、François Diederich、Ian Egle、Xiaokuai Hao、Ronghua Liu、Janusz Lusztyk、Jihai Ma、Michael A. McAllister、Yves Rubin、Kuangsen Sung、Thomas T. Tidwell、Brian D. Wagner
DOI:10.1021/ja9722685
日期:1997.12.17
The bisketenes 2 have been generated by flash photolysis, and the kinetics of their conversion to 1 have been studied by time-resolved infrared and ultraviolet spectroscopy. The rate constants of the ring closure of 2 are correlated by the ketene stabilization parameters (SE) and with calculated barriers. The rate constant of ring closure of the di-tert-butyl bisketene 2g to cyclobutenedione 1g is
环丁烯-1,2-二酮 (1) 和 1,2-双烯酮 (RCCO)2 (2) 的相互转化已针对不同的取代基组合 R = H、Me、t-Bu、Ph、Me3Si、CN、 Cl、Br、R1O、炔基和PhS。双烯酮 2 是通过闪光光解产生的,并且通过时间分辨红外和紫外光谱研究了它们转化为 1 的动力学。2 的闭环速率常数与乙烯酮稳定参数 (SE) 和计算的势垒相关。二叔丁基双烯酮 2g 至环丁烯二酮 1g 的闭环速率常数仅比二甲基类似物小 40 倍,显示出相当适中的空间位阻。quinoketene 2s 的闭环速度很快,但没有根据计算的几何和热力学因素预期的那么快。