STRAIGHTFORWARD SYNTHESIS OF 1-AMINO-2,2-DIALKYLCYCLOPROPANECARBOXYLIC ACIDS VIA SELECTIVE SAPONIFICATION OF 2,2-DIALKYLCYCLTOPROPANE-1,1-DICARBOXYLIC ESTERS AND CURTIUS REARRANGEMENT

Selective monosaponification of dimethyl 2,2-dialkylcyclopropane-1,1l-dicarboxylic esters afforded the corresponding 2,2-dialkyl-1-(methoxycarbonyl)cyclopropane-1-carboxylic acids, which were rearranged with diphenyl phosphoroazidate via a modified Curtius-type reaction to give methyl 2,2-dialkyl-1-[N-(alkoxycarbonyl)amino]cyclopropanecarboxylic esters. Selective deprotection of the carbamate or methyl cyclopropanecarboxylic ester was worked out, giving rise to a whole variety of ACC analogues. Straightforward ways to 1-amino-2,2-dialkylcyclopropanecarboxylic acids (2,2-dialkyl-ACC's) were developed.