作者:Harriet Ardill、Ronald Grigg、Visuvanathar Sridharan、Sivagnanasundram Surendrakumar
DOI:10.1016/s0040-4020(01)86199-8
日期:1988.1
decarboxylation, followed by intramolecular cycloaddtion of the resultant non-stabilised azomethine ylides. Evidence is produced for syn-anti dipole equilibration and it is found that intramolecular cycloadditions to a terminal alkyne involve only the anti-dipole and proceed via an exotransition state to give a single cycloadduct. In contrast, intramolecular cycloaddition to a terminal alkene involves
将一系列无环和环状仲α-氨基酸与含有最接近的末端烯烃或炔烃的芳基醛一起加热,会导致连续的缩合和脱羧,然后将所得的非稳定的甲亚甲酰亚胺分子内环加成。产生了顺-反偶极平衡的证据,并且发现分子内环加成至末端炔烃仅涉及反偶极并通过外过渡态进行以给出单个环加合物。相反,分子内环加成至末端烯烃涉及反偶极和顺偶极,在能量上优选俘获前者,导致两种立体异构体环加合物的混合物。