Synthesis and reactivity of 6-carbamoyl-5-phenyl-2,3,5,6-tetrahydro-1H-1,4-ethanobenzo[f]quinoline. X-Ray molecular structure of (4aR,5S,6R,10bR)-5-phenyl-2,3,4a,5,6,10b-hexahydro-1H-1,4-ethanobenzo[f]quinolin-6-yl acetate

Abstract

Cyclocondensation of 2-(2-cyano-1,2-diphenylethyl)quinuclidin-3-one 1 in the presence of sulfuric acid gave an intramolecular phenylation instead of lactam formation. The cyclic product was hydrogenated to give 6-carbamoyl-5-phenyl-2,3,4a,5,6,10b-hexahydro-1H-1,4-ethanobenzo-[f]quinoline. On treatment with LiAlH₄ the carbamoyl group was stereospecifically replaced by a hydroxy group. The alcohol was acetylated and the structure was confirmed by X-ray crystallography. The hydroxylation reaction is believed to proceed via a carbonitrile intermediate. In the presence of air the nitrile can be converted to a ketone which is then reduced to the alcohol with an overall retention of configuration.