In order to discuss the regioselectivity of nitrile oxide 1,3-dipolar cycloaddition to propyne, 1,3-dipolar cycloaddition reaction of substituted nitrile oxide (RCNO, R＝F, NO₂, OCH₃, OH, COOCH₃, CHO, CONH₂, H, CH₃) with propyne was studied using density functional theory at the 6-311＋＋G** level, and the reaction rates were calculated at different temperature from 200 to 400 K. The conclusions are that 5-substituted reaction of nitrile oxide with electron-deficient dipolarophile—propyne is dominant, while 4-substituted reaction of electron-deficient nitrile oxide with propyne is favored at relatively high temperature.

Key words: 1,3-dipolar cycloaddition, nitrile oxide, propyne, quantum chemical calculation, regioselectivity