TRIMETHYLSILYLKETENE - CYCLOADDITIONS OF KETENES AND ALDEHYDES

The cycloaddition of trimethylsilylketene with saturated aldehydes in the presence of a catalytic amount of BF3.Et2O resulted in the formation of the cis- and irons-2-oxetanones. Trimethylsilylketene reacted with α, β-unsaturated aldehydes, cinnamaldehyde, crotonaldehyde, furfural, and α-methylcinnamaldehyde, in the presence of BF3.Et2O, to yield trimethylsilyl dienoate esters. These esters are derived from the 2-oxetanones which underwent a silicon migration from carbon to oxygen accompanied by a ring-opening reaction. Dichloroketene and diphenylketene reacted with cinnamaldehyde to yield the corresponding 2-oxetanones, which readily decarboxylated to the substituted 1, 3-butadienes. © 1979, American Chemical Society. All rights reserved.