[reaction: see text] Photolysis of alpha-keto amides bearing 4-YC(6)H(4)O leaving groups at the position alpha to the keto group efficiently produces high yields of phenols when Y is an electron-withdrawing group or H. The photoelimination likely involves cleavage of zwitterionic intermediates produced via excited-state hydrogen transfer. When Y is an electron-donating group, competing excited-state
[反应:见正文]当Y为吸电子基团或H为基团时,带有4-YC(6)H(4)O的α-酮酰胺的光解有效地产生了高产率的
苯酚,这些残基位于酮基的α位光消除可能涉及通过激发态氢转移产生的两性离子中间体的裂解。当Y是一个给电子基团时,发生竞争性的激发态ArO-Cα键断裂成自由基,然后
重组产生1,3-光重排产物。