The photochemical preparation of ozonides by electron-transfer photo-oxygenation of epoxides
作者:A. Paul Schaap、Shahabuddin Siddiqui、Girija Prasad、Eduardo Palomino、Mark Sandison
DOI:10.1016/s0040-4020(01)96597-4
日期:1985.1
electron-transfer photo-oxygenation of epoxides in oxygen-saturated acetonitrile to form ozonides. Epoxides with oxidation potentials lower than 2 V vs SCE quench the fluorescence of DCA and are converted to the ozonides with DCA alone. Epoxides which do not quench the singlet excited state of DCA are unreactive under these conditions. However, the photo-oxygenation of these epoxides can be effected by addition
9,10-二氰基蒽(DCA)使在氧饱和的乙腈中的环氧化物的电子转移光氧合反应敏感,从而形成臭氧化物。与SCE相比,氧化电位低于2 V的环氧化合物会猝灭DCA的荧光,仅通过DCA即可将其转化为臭氧化物。在这些条件下,不会淬灭DCA的单重激发态的环氧化合物不会发生反应。然而,这些环氧化物的光氧化可以通过添加联苯(BP)作为催化剂或共敏化剂来实现。对顺式-和反式-2,3-二芳基环氧乙烷的反应的立体化学研究表明,两种同分异构的环氧化物都只转化为相应的顺式-臭氧化物。顺式和-的共同增感光氧合反式-2,3-二苯基环氧乙烷仅提供顺式-3,5-二苯基-1,2,4-三氧戊环。对于不需要BP共敏化的更容易氧化的2,3-二萘并氧杂蒽的电子转移光氧化,遵循相同的立体化学过程。萘基取代的臭氧化物的立体化学已经明确地由顺式-3,5-双(2'-萘基)-1,2,4-三氧戊环的X射线结构确定。通过顺式臭氧化制备相应的反式-臭氧化物-1