Reactions of methylene with ethers. Part 1.—Dimethyl ether, methyl ethyl ether, methyl n-propyl ether, methyl-isopropyl ether, methyl-t-butyl ether and tetrahydrofuran

Abstract

The reactions of methylene, produced by the photolysis of both ketene and diazomethane, with a number of simple ethers have been studied. Most of the data obtained refer to the gas phase but some liquid-phase results are also reported. Methylene in its singlet state has been found to insert in the various carbon hydrogen bonds in a near random fashion. Triplet methylene gives rise to products by attack predominantly on the carbon hydrogen bonds of carbon atom α to the oxygen atom of the ethers. Because of these differences it has been possible to estimate the percentage of singlet and triplet methylene present under various conditions. Products were obtained which correspond formally to those expected from the insertion in a carbon-oxygen bond. Except for cyclic ethers these probably result from abstraction followed by recombination reactions. Only singlet methylene appears to undergo a displacement reaction which with methyl alkyl ethers results in the formation of dimethyl ether and an olefin.