Photochemistry of α-Diketones in Carbohydrates: Anomalous Norrish Type II Photoelimination and Norrish-Yang Photocyclization Promoted by the Internal Carbonyl Group
作者:Dimitri Alvarez-Dorta、Elisa I. León、Alan R. Kennedy、Angeles Martín、Inés Pérez-Martín、Concepción Riesco-Fagundo、Ernesto Suárez
DOI:10.1002/chem.201303843
日期:2014.2.24
regioselectivity of the hydrogen atom transfer (HAT) in Norrish type II photochemical processes. We observed that the 1,5‐HAT regioselectivity can be switched between the two potentially abstractable syn‐1,3‐diaxial hydrogens at H6 and H8. Highly unusual photoproducts from Norrish type II photoelimination and Norrish–Yang photocyclization initiated by the excited internal carbonyl group were obtained
一系列的置于作为1α-丙酮酰系绳4α二酮d -glucopyranose和d,以便确定在上型Norrish氢原子转移(HAT)的区域选择性的推拉和立体电子效应的影响,制备-glucopyranosiduronic酸骨架二,光化学过程。我们观察到1,5-HAT区域选择性可以在两个可能抽象的syn之间进行切换H6和H8处的-1,3-双轴氢。从Norrish II型光消除和由激发的内部羰基引发的Norrish-Yang光环化获得了非常不寻常的光产物,在某些情况下,合成产率很高。通过结晶状态下的光化学实验研究了Norrish II型光消除中的1,5-HAT过渡态。