März M, Chudoba J, Kohout M, Cibulka R
Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
Central Laboratories, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
Org Biomol Chem. 2017 Mar 1;15(9):1970-1975. doi: 10.1039/c6ob02770a.
The usefulness of flavin-based aerial photooxidation in esterification under Mitsunobu reaction conditions was demonstrated, providing aerial dialkyl azodicarboxylate recycling/generation from the corresponding dialkyl hydrazine dicarboxylate. Simultaneously, activation of triphenylphosphine (PhP) by photoinduced electron transfer from flavin allows azo-reagent-free esterification. An optimized system with 3-methylriboflavin tetraacetate (10%), oxygen (terminal oxidant), visible light (450 nm), PhP, and dialkyl hydrazine dicarboxylate (10%) has been shown to provide efficient and stereoselective coupling of various alcohols and acids to esters with retention of configuration.
基于黄素的空气光氧化在Mitsunobu反应条件下的酯化反应中的实用性得到了证明，可从相应的二烷基肼二羧酸酯中回收/生成空气二烷基偶氮二羧酸酯。同时，黄素光致电子转移对三苯基膦（PhP）的活化使得酯化反应无需偶氮试剂。已证明，由四乙酸3-甲基核黄素（10%）、氧气（终端氧化剂）、可见光（450nm）、PhP和二烷基肼二羧酸酯（10%）组成的优化体系能实现各种醇和酸高效、立体选择性地偶联生成酯，并保持构型。
