Preparation of E-(2-substituted-1-methylethylidene)indanones derived from monic acid

Article abstract of DOI:10.1016/S0040-4039(00)73095-4

Alkylation of the lithium dienolate of the monic acid hydroxamate (3) with o-bromo(bromomethyl) benzene or heteroaromatic derivatives gave α-alkylated products (5). This alkylation procedure was surprisingly catalysed by 4- dimethylaminopyridine. Metal-halogen exchange with t-butyl lithium occurred with concomitant intramolecular cyclisation to give a mixture of the deconjugated ketones (6). Reconjugation with potassium t-butoxide stereoselectively produced the E-isomer (7). Deprotection gave the monic acid derived ketone (1).