A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the ex...A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the expected nucleophilic photo-S_(RN) 1 substitution originating from the carb- anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MO correlation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con- trast is reasonably attributed to the variation in energy gap between π~*c-o and π~*Ar of (ArNu)- Usually, the odd electron of (ArNu)- is weightly populated at π~*c-o, however, the diminished priv- ilege of π~*c-o in menthyl propionate promotes a dominant population of the odd electron at π~*Ar, which leads to the fragmentation of (ArNu)- into the starting carbanion and aryl radical.展开更多
基金the National Natural Science Foundation of China.
文摘A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the expected nucleophilic photo-S_(RN) 1 substitution originating from the carb- anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MO correlation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con- trast is reasonably attributed to the variation in energy gap between π~*c-o and π~*Ar of (ArNu)- Usually, the odd electron of (ArNu)- is weightly populated at π~*c-o, however, the diminished priv- ilege of π~*c-o in menthyl propionate promotes a dominant population of the odd electron at π~*Ar, which leads to the fragmentation of (ArNu)- into the starting carbanion and aryl radical.
