PHOTOISOMERIZATION OF ACYCLIC CONJUGATED CYCLOPROPYL CARBONYL COMPOUNDS

The photochemistry of the acyclic vinylcyclopropane carbonyl chromophore has been studied. Using Corex-filtered light, dihydrofurans (4-6), δ,εunsaturated acids (7 and 8), and epoxycyclobutanes (9 and 10) were found. The mechanism for the formation of these materials are discussed, and all reactions involve conjugative opening of the cyclopropane ring (eq 6 and 7). The formation of a ketene from an acyclic aldehyde is a new process and it has been shown to proceed intramolecularly (eq 8). © 1969, American Chemical Society. All rights reserved.