Mannich reaction in a number of six-membered heterocyclic ?,-ketones. X. Stereochemistry of the reduction and phenylation of 2, 2-dimethyl-5-dimethylaminomethyl-4-oxotetrahydropyran

Abstract

2, 2-Dimethyl-5-dimethylaminomethyl-4-oxotetrahydropyran was subjected to reduction with lithium aluminum hydride, sodium borohydride, aluminum isopropoxide, and lithium in liquid ammonia, to catalytic hydrogenation over Raney nickel, and phenylation with phenyllithium. The quantitative ratios in the resulting mixtures of stereoisomeric 2, 2-dimethyl-5-dimethylaminomethyl-4-hydroxytetrahydropyrans and their dependence on the character of the reducing agents were established by means of gas — liquid chromatography and PMR spectroscopy. The individual geometrical isomers of the amino alcohols were isolated, and their three-dimensional structures were studied by means of their PMR and IR spectra.