Novel Route to Triethylsilyl-Substituted Cyclopropanes

Abstract : Radical adducts of S-α-ketonyl dithiocarbonates (xanthates) to triethyl vinylsilane are converted into triethylsilyl-substituted cyclopropanes upon ozonolysis followed by exposure to 1,4-dibromobutane and Cs2CO3/18-crown-6 in refluxing acetonitrile. The sequence works best with phenacyl type adducts, and the use of the less bulky trimethysilyl (TMS) derivatives results in extensive desilylation.