REACTION OF (TRIMETHYLSILYL)KETENE WITH SILYLATED KETENE ACETALS

We have reported on the [2 + 2] cycloaddition of (tri-methylsilyl) ketene with electron-rich tetraalkoxyethylenes to yield products that on hydrolysis give semisquaric acid.1The cycloaddition of this ketene with dimethyl- and di-ethylketene acetals under rather vigorous conditions gave silicon-containing cyclobutanones.2 It is pertinent to realize that ketene acetals are electron-rich olefins and well suited for cycloaddition reactions with this isolable and stable ketene. We now wish to describe the reaction of (trimethylsilyl)ketene (1), with some readily available O-silylated ketene acetals to yield acyclic unsaturated esters. © 1990, American Chemical Society. All rights reserved.