Absolute configuration and predominant conformations of 1,1-dimethyl-2-phenylethyl phenyl sulfoxide

Abstract

The absolute configuration of the (+)-1,1-dimethyl-2-phenylethyl phenyl sulfoxide is determined to be (R), using three different chiroptical spectroscopic methods, namely vibrational circular dichroism (VCD), electronic circular dichroism (ECD) and specific rotation. Four solution conformations are identified for 1,1-dimethyl-2-phenylethyl phenyl sulfoxide. In each of the methods used, experimental data for the enantiomers of 1,1-dimethyl-2-phenylethyl phenyl sulfoxide were measured in the solution phase and concomitant quantum mechanical calculations of corresponding properties were carried out using density functional theory with B3LYP functional and 6-31G* and 6-31+G basis sets. Additional VCD and ECD calculations were also undertaken with 6-311G(2d,2p) basis set. A comparison of theoretically predicted data with the corresponding experimental data has allowed us to elucidate the absolute configuration and predominant conformations of (+)-1,1-dimethyl-2-phenylethyl phenyl sulfoxide.