Structural Effects on Interconversion of Oxygen-Substituted Bisketenes and Cyclobutenediones
作者:Nanyan Fu、Annette D. Allen、Shinjiro Kobayashi、Thomas T. Tidwell、Sinisa Vukovic、Takeshi Matsuoka、Masaaki Mishima
DOI:10.1021/jo702312t
日期:2008.3.1
of oxygen to the cyclobutenediones 5f−h by the ArO substituents compared to alkoxy groups and to angle strain in the bridged product cyclobutenedione 5i. The reactivities of the ArO-substituted bisketenes 6f−h in CH3CN varied by a factor of 50 and gave an excellent correlation of the observed rate constants log k with the σp constants of the aryl substituents. Computational studies at the B3LYP/6-31G(d)
Cyclobutenediones 5与HO(二取代的一个),的MeO(b),环氧乙烷(Ç),我-Pro(d),吨-BuO(ë)的PhO(˚F),4- MeOC 6 H ^ 4 O(克),4- -O 2 NC 6 H 4 O(h)和3,4-桥接OCH 2 CH 2 O(i)取代基在激光快速光解后得到相应的双烯酮6a - i,通过在2075至2106和2116至2140 cm - 1之间的独特的双重红外吸收来检测。对于6b - e组,回到环丁二烯的开环反应性最大,在25°C下6e(RO = t -BuO)在异辛烷中的速率常数最高,为2.95×10 7 s - 1。6a(RO = OH,k = 2.57×10 6 s - 1在CH 3 CN中),而6f - i的反应性最低,速率常数最低,为3.8×10 4s - 1在CH 3 CN中放置6h(RO = 4-O 2 NC 6 H 4 O)。6f -