84353-98-0Relevant academic research and scientific papers
INVESTIGATION OF THE STEREOCHEMISTRY AND PREFERRED CONFORMATIONS IN 2-SUBSTITUTED 4,5-DIISOPROPYL-1,3-DIOXOLANES BY PMR SPECTROSCOPY
Bukin, V. A.,Zakharov, K. S.,Gren', A. I.
, p. 547 - 553 (2007/10/02)
The cis (syn-anti) and trans isomers of 2-substituted 4,5-diisopropyl-1,3-dioxolanes were obtained, and their PMR spectra were studied.The molecular conformations of the obtained compounds were studied by analysis of the spin-spin coupling constants and the increments of the chemical shifts.The cis-anti isomers exist in the preferred half-chair conformation with the pseudoequatorial arrangement of the substituent at the C2 atom, whereas in the syn isomers the interaction between the substituents at the C2, C4, and C5 atoms flattens the ring, approximating it to the envelope conformation.The ring is also flattened in the trans isomers, and the substituents at the C4 and C5 atoms approximate to a pseudoaxial orientation, reducing the torsional angle between H4 and H5 atoms to a value of less than 120 deg.The averaged (or pseudorotation) conformation of the molecules of the trans isomers differs from the conformation of the cis isomers.
