Carbon-13 and proton magnetic resonance spectra of 2,4-disubstituted 3,3-diphenyltetrahydrofurans derived from isomethadone and isomethadol

Proton and carbon-13 nmr spectra for cis- and trans-2-ethyl-3,3-diphenyl-4-methyltetrahydrofurans and 2-ethylidene-3,3-diphenyl-4-methyltetrahydrofuran, derived from the pyrolysis of the quaternary ammonium salts of the diastereomeric isomethadols and isomethadone, respectively, are reported. ¹H and ¹³C chemical shifts and ¹H-¹H coupling constants have been assigned in each case. The isomeric teterahydrofurans have been analyzed in terms of a half-chair conformation, and an envelope conformation for the ethylidene derivative.