A convenient method for the preparation of N-substituted 1-acetonylaminocyclopropanes from acetoacetic ester ethylene acetal

Reaction of 1-acetonyl-1-tosyloxycyclopropane with primary or secondary ami nes affords the corresponding 1-acetonyl-1-aminocyclopropanes in quantitati ve yields. The starting tosylate was prepared from acetoacetic ester ethyle ne acetal in three steps through its cyclopropanation with ethylmagnesium b romide in the presence of 0.2 equivalent of titanium (IV) isopropoxide, fol lowed by deprotection of the carbonyl group and tosylation.