Reactions of zinc enolates derived from 1-aryl-2,2-di-bromoalkanones with 2-acyl-3H-benzo[f]chromen-3-ones, 6-bromo-2-oxochromene-3-carboxamides, and 3-oxo-3H-benzo[f]chromene-2-carboxamides

Zinc enolates derived from substituted 1-aryl-2,2-dibromoalkanones reacted with 2-acyl-3H-benzo-[f]chromen-3-ones to give 1-alkyl-1-aroyl-1a-acyl-1a,9c-dihydro-1H-3-oxacyclopropa[c]phenanthren-2-ones which were formed as a single stereoisomer. Reactions of the same zinc enolates with 6-bromo-2-oxochromene-3-carboxamides (piperidides and morpholides) afforded 1-aroyl-6-bromo-1-alkyl-1a-piperidino(morpholino)carbonyl-la,7b-dihydrocyclopropa[c]chromen-2-ones with high stereoselectivity. Likewise, 1-benzoyl-1-methyl-1a-morpholinocarbonyl-1a,9c-dihydro-1H-3-oxacyclopropa[c]phenanthren-2-one was obtained by reaction with 3-oxo-3H-benzo[f]chromene-2-carboxylic acid morpholide.