1, 3-DIPOLAR CYCLOADDITIONS OF AZOMETHINE YLIDE WITH ELECTRON-RICH OR NORMAL OLEFINS

1. 氮化吡啶中n取代基对反应的影响研究了分别含n -苯基或n -苯甲酰基团的(α、β-不饱和γ、δ-环氧亚胺酯1和2与烯烃的光化学和热反应。1与丙烯腈的光化学反应得到的加合物产率为45%。另一方面，1和2的热反应和2的光反应没有产生加合物，但通过C(γ)， O-bong裂解形成了胺。氮取代基与氮吡啶环结合后，易于裂解氮吡啶中的C(γ), O-bong。研究了α、β、α-不饱和γ、δ-环氧亚胺体系在α-位置上具有两个吸电子基团和烯烃的反应。二腈3和二酯4与丙烯腈的光化学反应得到了前面所得到的加合物。此外，二腈- 3与异戊二烯和醋酸乙烯成功地进行了新的光环加成反应。丙烯腈加合物的产率随氮吡啶侧链缺电子量的增加而降低。具有3位取代基的叠氮嘧啶的反应为了阐明反应机理，进行了3-甲基和3-苯基取代叠氮嘧啶5和6与烯烃的反应。5的光化学反应和热反应表明，叠氮啶的开环反应和烯烃的环加成反应并没有同步进行。另一方面，在光化学反应和热化学反应中，叠氮吡啶6发生开环和环加成反应，形成加合物。3-对氰苯基（更缺电子取代基）偶氮吡啶不与异戊二烯和醋酸乙烯发生反应。叠氮嘧啶5和6与分子氧光化学反应生成二恶唑烷及其分解的化合物。结果表明，该反应中间体具有双基性。

1. Effects of the N-Substituent in Aziridine on the ReactionThe photochemical and thermal reactions of (α, β-unsaturated γ, δ-epimino esters 1 and 2 possessing respectively N-phenyl or N-benzoyl group and olefins were studied. The photoreaction of 1 with acrylonitrile gave the adduct in 45% yield. On the other hand, the thermal reactions of 1 and 2 and the photoreactions of 2 afforded no adduct, but enamines formed via C(γ), O-bong cleavage. The N-substituents conjugated with the aziridine ring tend to cleave the C(γ), O-bong in aziridine.2. Effects of the α-Substituent in the side chain on the ReactionThe reactions of α, β-unsaturated γ, δ-epimino system possessing two electron withdrawing groups in α-position and olefins were investigated. The photoreactions of the dinitrile 3 and the diester 4 and acrylonitrile gave the adducts as obtained before. Furthermore, the novel photocycloadditions of the dinitrile 3 proceeded with isoprene and vinyl acetate successfully.The yields of the acrylonitrile adducts decreased with increasing the electron deficiency in the side chain of aziridine.3. Reactions of Aziridines Possessing Substituent at 3-PositionIn order to clarify the reaction mechanism, the reactions of 3-methyl and 3-phenyl substituted aziridines 5 and 6 and olefins were performed. The photochemical and thermal reaction of 5 shows that the ring-opening of aziridine and cycloaddition with olefins did not proceed concertedly. On the other hand, on the photochemical and thermal reactions the aziridine 6 underwent ring-opening and cycloaddition concertedly leading to adducts. The 3-p-cyanophenyl (more electron deficient substituent) aziridine did not react with isoprene and vinyl acetate.The aziridines 5 and 6 react with molecular oxygen photochemically affording the dioxazolidine and its decomposed compounds. The results may suggest that the reaction intermediate possesses biradical character.