Photosensitized Electron Transfer Promoted Reductive Activation of Carbon−Selenium Bonds To Generate Carbon-Centered Radicals: Application for Unimolecular Group Transfer Radical Reactions
作者:Ganesh Pandey、K. S. Sesha Poleswara Rao、K. V. Nageshwar Rao
DOI:10.1021/jo960805i
日期:1996.1.1
presented in this paper explores the mechanistic aspects and synthetic potentials of photosensitized electron transfer (PET) promoted reductive activation of organoselenium substrates. PET activation of substrates 1-5 is achieved through a photosystem comprised of light-absorbing 1,5-dimethoxynaphthalene (DMN) as electron donor and ascorbic acid as co-oxidant. The fluorescence quenching of (1)DMN by organoselenium
本文提出的研究探索了光敏电子转移(PET)促进有机硒底物还原活化的机理和合成潜力。基材1-5的PET活化是通过一个光系统实现的,该系统由吸光的1,5-二甲氧基萘(DMN)作为电子给体,而抗坏血酸作为助氧化剂。有机硒化合物1-5对(1)DMN的荧光猝灭,荧光猝灭速率常数与1-5的还原电势的相关性以及1-5的光解离量子产率对其浓度的依赖性表明电子的发生(1)DMN和1-5之间的传输(ET)进程。在(1)DMN和抗坏血酸的存在下,有机硒底物(R(2)CHSePh)的稳态光解导致-C-Se-键断裂,从而产生碳中心自由基和PhSe(-)物种R(2)CH-SePh&(r-)(*)的中间体。对于单分子基团转移自由基序列,用于-C-Se-键的还原活化的机制解释和观察到的裂解模式的合成效用得到扩展。