1,3-dipolar cycloadditions of photoinduced carbonyl ylides. Part 3: Photoreactions of alpha,beta-unsaturated gamma,delta-epoxy dinitrile, alpha-cyanoester, and diester with various dipolarophiles

Photoinduced carbonyl ylide (A) from alpha,beta-unsaturated gamma,delta-epo xy dinitrile (1) undergoes 1,3-dipolar cycloaddition with enol ethers, lead ing to tetrahydrofuran system with high regioselectivity in moderate yield. However, The cycloadditions of A with nonactivated and electron-deficient olefins and with C=N containing dipolarophiles gave the corresponding adduc ts slightly. The reactivity for the cycloaddition of alpha-cyano ester (8) and diester (9) with ethyl vinyl ether decreases.