title: Absolute configuration and conformational stability of (+)-2,5-dimethylthiolane and (-)-2,5-dimethylsulfolane.
abstract: Enantiopure (+)-2,5-dimethylthiolane and (-)-2,5-dimethylsulfolane were prepared using literature procedures and investigated using vibrational circular dichroism (VCD). Experimental absorption and VCD spectra of (+)-2,5-dimethylthiolane and (-)-2,5-dimethylsulfolane in CCl(4) solution in the 2000-900 cm(-)(1) region were compared with the ab initio predictions of absorption and VCD spectra obtained with density functional theory using the B3LYP/6-311G(2d, 2p) basis set for different conformers of (2R,5R)-2,5-dimethylthiolane and (2R,5R)-2,5-dimethylsulfolane. This comparison indicates that (+)-2,5-dimethylthiolane is of the (2R,5R)-configuration and has two predominant conformations in CCl(4) solution. In addition, (-)-2,5-dimethylsulfolane is of (2R,5R)-configuration and has only one predominant conformation. The stereochemical assignment is in agreement with literature.
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: P L
authors.initials: PL
authors.lastname: Polavarapu
authors.forename: C J
authors.initials: CJ
authors.lastname: Rizzo