Experiments concerning the photochemical condensation of 3-phenyl-2H-azirines 1 with aliphatic and aromatic aldehydes to 3-oxazolines 4 are fully described (cf. scheme 1). Photochemically nitrile methylides of type 2 are first formed, which then very quickly react thermally with the aldehydes in a regiospecific manner to give the 3-oxazolines 4. Azirines monosubstituted in position 2 (lb and 1c) give
                                    关于3-苯基2的光
化学缩合实验ħ -azirines 1与脂肪族和
芳香族醛-3-
恶唑啉4中充分描述(CF。方案1)。首先形成光
化学类型为2的腈亚甲基,然后以区域特异性方式非常快速地与醛进行热反应,生成3-
恶唑啉4。在位置2(l b和1 c)上单取代的嗪生成顺式,反-
恶唑啉异构体的混合物,其中顺式异构体占主导地位。环加成反应的立体选择性可以通过简单的模型来合理化(方案10)。