Stereospecificity of the 3JCH spin-spin coupling constants in bicyclic cis-diaziridines. Stereochemistry of 2,4,6-trialkyl-1,3,5-triazabicyclo[3.1.0]-hexanes

Stereospecificity of the ³J_C,N,C,H spin-spin coupling constants (³J^trans > J^gauche) in the ¹³C NMR spectra of 1,5-diaza- and 1,3,5-triazabicyclo[3.1.0]hexanes was observed. Proceeding from this, the preferred conformations of the d, Z and meso isomers of 2,4,6-trialkyl-1,3,5-triazabicyclo[3.1.0]hexanes were established, and a mechanism for the interconversion of these isomers via openings of the five-membered ring and an imino-enamine equilibrium was proposed. It is also shown that the stereochemical result of the Schmitz reaction is determined in the step involving cyclization of the iminium intermediate.Communication 42 from the series Asymmetric unbridged nitrogen. See [1] for communication 41.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1348–1354, October, 1985.The authors thank N. L. Zaichenko for his assistance in measuring the NMR spectra.