Energy of Concert and Origins of Regioselectivity for 1,3-Dipolar Cycloadditions of Diazomethane
Mechanisms and regioselectivities in 1,3-dipolar cycloadditions of diazomethane with alkenes have been investigated with density functional theory (DFT) and DLPNO-CCSD(T) computations. The concerted but asynchronous pathway is shown to be favored by at least 6 kcal/mol over the stepwise diradical pathway in all diazomethane-alkene cycloadditions. Frontier molecular orbital calculations indicate a dominant HOMOdipole -> LUMOdipolarophile interaction in diazomethane cycloadditions involving electron-deficient alkenes, whereas for electron-rich alkenes, both frontier interactions contribute significantly, and the regioselectivity is governed by frontier coefficients.
Chen, Shuming, Tuo Hu, and K.N. Houk. 2021. "Energy of Concert and Origins of Regioselectivity for 1,3-Dipolar Cycloadditions of Diazomethane." Journal of Organic Chemistry 86(9): 6840-6846.
American Chemical Society
Journal of Organic Chemistry
Chemistry and Biochemistry
Diradical mechanism, Orientation, Reactivity, Diazoalkanes