Japan Science and Technology Agency, CREST, Chiyodaku, Tokyo, Japan.
Photochem Photobiol Sci. 2011 Sep;10(9):1469-73. doi: 10.1039/c1pp05056g. Epub 2011 May 3.
The Paternò-Büchi (PB) reaction of geraniol derivatives 1, which contain allylic alcohol functionality and unfunctionalized double bonds, with benzophenone was investigated to see the effect of the hydroxyl group on the regioselectivity of the oxetane formation, i.e., 2/3. At low concentration of geraniol (1a), oxetanes 2a and 3a were formed in a ratio of 2a/3a = ca. 50/50. The oxetane 2a is derived from the PB reaction at the allylic alcohol moiety, whereas the PB reaction at the unfunctionalized double bond produces the oxetane 3a. The PB reaction of the hydroxy-protected methyl ether 1b and acetate 1c gave selectively oxetanes 3b,c derived from the reaction at the more nucleophilic double bond, 2/3∼ 15/85. The hydroxyl-group effect was found to be small, but apparently increased the formation of 2a in the PB reaction with geraniol (1a).
我们考察了含有烯丙醇官能团和非官能化双键的香叶醇衍生物 1 与二苯甲酮的 Paternò-Büchi (PB) 反应，以了解羟基对环氧乙烷形成的区域选择性的影响，即 2/3。在低浓度的香叶醇（1a）下，生成了环氧乙烷 2a 和 3a 的比例约为 2a/3a = ca. 50/50。环氧乙烷 2a 来自于烯丙醇部分的 PB 反应，而在非官能化双键的 PB 反应则生成了环氧乙烷 3a。羟基保护的甲醚 1b 和乙酸酯 1c 的 PB 反应选择性地生成了来自更亲核双键的环氧乙烷 3b,c，2/3∼ 15/85。羟基效应虽小，但显然增加了香叶醇（1a）的 PB 反应中 2a 的生成。
