MASS SPECTRA OF CYCLOBUTYL AND CYCLOPROPYLCARBINYL METHYL ETHERS AND METHANOLYSIS OF BICYCLOBUTANE

The mass spectral fragmentation patterns of cyclobutyl and cyclopropylcarbinyl methyl ethers were found to be similar and the mechanisms of the fragmentations were evaluated by use of deuterium-labeled material and by means of high-resolution mass spectrometry. In both materials the base peak was m/e 58, corresponding to the loss of ethylene. The mechanism of the acid-catalyzed addition of methanol to bicyclobutane was studied using the above mass spectral results. The addition was not concerted but proceeded via protonation to yield a bicyclobutonium ion (or equivalent activated complexes) which partially equilibrated before the nucleophilic attack of methanol occurred. When 1,3-butadiene in methanol was irradiated with ultraviolet light, cyclobutvl and cyclopropylcarbinyl methyl ethers were formed in low yield. These ethers were shown to be derived in a dark reaction of methanol with bicyclobutane. © 1969, American Chemical Society. All rights reserved.