Photolysis of alkyl-substituted 2-(2-oxa-3-butenyl)cyclopent-2-enones gives rise to derivatives of bicyclo[2.1.1]hexanes (“rule of five” product), and α-methylenecyclopentanones(photo-Claisen rearrangement). Methyl substitution remote from the bond forming centers produces a regioselective reaction yielding only the “rule of five” product.
烷基取代的2-(2-氧杂-3-
丁烯基)环戊-2-烯酮的光解反应生成
双环[2.1.1]己烷(“五律”产物)和α-亚甲基
环戊酮(光-克莱森)的衍
生物重新排列)。远离键形成中心的甲基取代会产生区域选择性反应,仅产生“五个规则”产物。