碘化钠-三苯基膦介导的光氧化还原醛亚胺烷基化

Sodium Iodide-Triphenylphosphine-Mediated Photoredox Alkylation of Aldimines

电子给受体(EDA)络合物参与的光氧化还原反应近十年来备受关注.新近发现的碘化钠-三苯基膦-N-羟基邻苯二甲酰亚胺羧酸酯EDA络合物已被用于发展多种净氧化还原中性的光反应.本工作将该EDA络合物用于建立净还原性光反应体系,发展了无需光敏剂的可见光促进的醛亚胺自由基加成反应.该反应不仅能以高产率得到仲、叔、α-杂原子取代烷基自由基加成产物,而且通常反应性不佳的伯烷基自由基以及富电子或仲苄基自由基均能得到较高产率,为合成非天然氨基酸和胺类化合物提供了高效可靠的新方法.

The photoredox reactions involving electron donor-acceptor(EDA)complexes have attracted significant attentions in the last decade.Very recently,the sodium iodide-triphenylphosphine-N-acyloxyphthalimide EDA complex has been discovered and employed in developing several net redox-neutral photoreactions.Herein,the EDA complex has been applied in a net reductive setup for the first time to establish a photoredox alkylation of aldimines without photosensitizer.The reaction affords not only high yields for secondary,tertiary andα-heterosubstituted alkyl radicals,but also high yields for primary alkyl radicals,and moderate to high yields for electron-rich or secondary benzylic radicals,two difficult groups of radicals in previous studies.This work provides an efficient and reliable approach for the synthesis of unnatural amino acids and amines.