Photoinduced Electron Transfer Reactions in Chiral Reaction Media

1.不同的手性猝灭剂对S-(+)-和R-(-)-2，2‘-二甲基-1，1’-联苯并[1a]和[1b]的荧光猝灭有明显的手性识别作用。猝灭速率取决于猝灭剂的结构、给电子能力和手性。对映体对(+)-和(-)-N-(α-甲基苄基)-2，5-二甲基吡咯对1a的荧光猝灭是最大的手性分辨。手性猝灭剂对1a和芳香胺(如二甲基苯胺(2))产生的发光激基络合物的荧光猝灭也观察到手性识别。(+)-肉桂酸薄荷酯对1a/2和1b/2体系的激基缔合物荧光猝灭的kqtau比最大值为1.08，并随溶剂极性的增加而减小。这些结果表明，手性猝灭剂与手性激基络合物以对映体选择性的方式相互作用。研究了含薄荷基和胆固醇基的手性增敏剂1，4-二氰基萘和9，10-二氰基菲催化的醇与芳烃的光化学极性加成反应。2-胆甾氧甲基-1，4-二氰基萘敏化的1，1-二苯基丙烯与甲醇的反Markovnikov加成反应显示出最大值，对映体过量为27%。1-或2，3-位(S)上含有手性烷氧羰基(S)的呋喃和萘衍生物在分子间和分子内的光环加成反应分别以非对映选择性的方式得到(4+4)环加成产物和笼状化合物。此外，还揭示了产物的区域化学受激基复合体的偶极矩控制。

The title subject was investigated and the following results were obtained :1. Chiral discrimination is observed in the fluorescence quenching of S- (+) -and R- (-) -2,2'-dimethyl-1,1'-bianthryls (1a and 1b) by a variety of chiral quenchers. Quenching rates are varied depending on the structures, electron-donating abilities, and chiralities of the quenchers. The largest chiral discrimination is found in the fluorescence quenching of 1a by the enantiomer pair (+) -and (-) -N-(alpha-methylbenzyl) -2,5-dimethylpyrrole.2. Chiral discrimination is also observed in the fluorescence quenching of emissive exciplexes generated from 1a and aromatic amines such as dimethylaniline (2) by chiral quenchers. The kqtau ratio in the fluorescence quenching of the exciplex emission of 1a/2 and 1b/2 systems by (+) -menthyl cinnamate in benzene shows a maximum value of 1.08, and is decreased with increasing polarity of solvents. These results indicate that the chiral quenchers interact with chiral exciplexes in a enantioselective manner.3. Photochemical polar additions of alcohols to arylalkenes catalyzed by chiral sensitizers such as 1,4-dicyanonaphthalene and 9,10-dicyanoanthracene bearing menthyl and cholesteryl group are investigated. Anti-Markovnikov addition of methanol to 1,1-diphenylpropene sensitized by 2-cholesteryloxymethyl-1,4-dicyanonaphthalene shows a maximum value, a 27% enantiomeric excess.4. Inter- and intramolecular photocycloadditions between furan and naphthalene derivatives having chiral alkoxycarbonyl group (s) at 1- or 2,3-position (s) of naphthalene ring give (4+4) cycloadducts and cage compounds in a diastereoselective manner, respectively. Moreover, it is revealed that the regiochemistry of products is governed by dipolar moments of exciplexes.