Ethylene derivatives cyclopropane ring

Sodium hydride dimethyl sulfoxide Ring closures with sulfoxonium and sulfonium salts Synthesis of oxido compounds from oxo compounds Cyclopropanes from ethylene derivatives... 

Klemm (16) and Lee and coworkers (17) have examined the effect of various solvents on the photochemistry of cyclobutanone. By monitoring the quantum yields for formation of ethylene (B-cleavage product) and cyclopropane (decarbonylation product) in different solvents, they were able to demonstrate a significant reduction in the quantum yields for product formation in methanol as compared to other hydrocarbon solvents. Whereas the quantum yield of ethylene formation was found to be essentially solvent insensitive, that for cyclopropane formation was found to be somewhat solvent sensitive. This suggested that B-cleavage and decarbonylation do not result from the same immediate precursor. Since ring-expansion derivatives have not been isolated from photolyses carried out in saturated hydrocarbon solvents, the importance of this process under these conditions remains to be determined. Irradiation of cyclobutanone in the presence of 1,3-penta-diene (17,59) or 1,3-cyclohexadiene (16) did not appear to affect the quantum yields for ketone disappearance or product appearance. 

Substitution of the ethylenic carbons in a conjugated enyne by either an electropositive group in the 3-position or by an electronegative group in the 4-position favors addition to the acetylenic group. G. F. Bettinetti, G. Desimoni, and P. Griinanger, G. 94, 91 (1964) cyclopropane ring from ethylene derivatives in methanol s. F. Wessely and A. Eitel, M. 95, 1577 (1964). 

Ethylene derivatives from cyclopropane ring with deearhoxylation... 

Cyclopropane ring or methylene compds. from ethylene derivs. and 1,1-dihalides Silyloxycyclopropane ring or a-siloxymethylene compds. from enoxysilanes... 

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