ROTATIONAL SPECTROSCOPY AND RING-PUCKERING CONFORMATION OF 3-HYDROXYTETRAHYDROFURAN

Abstract

The ring puckering conformation of 3-hydroxytetrahydrofuran, a five-membered heterocyclic ring, has been determined from rotational spectroscopy. Rotational constants for the normal isotopomer are A=5581.8230(7), B=3638.8316(7), and C=2924.7410 (7)MHz; rotational spectra were also recorded for four $^{13} C$ isotopic species in natural abundance. The best in structure is a $C^{4\prime}$, endo conformation with an intramolecular hydrogen bond from the hydroxyl to the ring oxygen. Projections of the dipole moment on the inertial axes. $\mu_{a} =0.956 (1) D$, $\mu_{b}=0.875 (2) D$, and $\mu_{c}= 1.050$ (2) D, were determined from Stark effect measurements. The experimental structure is nearly identical to the lowest energy ab initio conformation ($MP2/6-31+G^{\ast \ast}$).