Competitive Enantiodifferentiating Anti-Markovnikov Photoaddition of Water and Methanol to 1,1-Diphenylpropene Using A Sensitizing Cyclodextrin Host
作者:Gaku Fukuhara、Tadashi Mori、Yoshihisa Inoue
DOI:10.1021/jo9012628
日期:2009.9.4
quenched in more hydrophobic solvents (≥50% methanol), where the fluorophore is not included in the cavity and allows the external attack of DPP to form an exciplex in the bulk solution. Upon irradiation in aqueous solutions of different methanol contents, competitive photoaddition of water and methanol to DPP occurred to give chiral water adduct 3 and methanol adduct 4, favoring the latter product by
UV-vis,圆二色性(CD),荧光和NMR光谱研究新合成的敏化主体6-(5-cyanonaphthyl-1-carboamido)-6-deoxy-β-cyclodextrin的自包含行为(1),表明1的萘部分在甲醇水溶液中在环糊精边缘上侧向栖息,但被浅层包含,并在水中的腔中略微倾斜。客体底物1,1-二苯丙烯(DPP)与主体1的络合的UV-vis和CD光谱检查显示DPP与1的化学计量比为1:1的络合物的形成。加入DPP可有效地淬灭1的萘基荧光在低甲醇含量(≤25%)的水溶液中,但在更多疏水性溶剂(≥50%甲醇)中的淬灭效率较低,其中荧光团不包含在空腔中,并允许DPP的外部侵蚀在分子中形成激基复合物批量解决方案。在不同甲醇含量的水溶液中辐照后,发生了水和甲醇与DPP的竞争性光加成,生成了手性水加合物3和甲醇加合物4,由于甲醇的亲核性较高,因此后者的收率提高了2.5倍。在高甲醇溶液中,光加合