Stereodynamics and absolute configuration of stereolabile atropisomers in 2,2-dimethyl-1-aryl-1-indanols.
We describe herein the investigation of the stereodynamic processes occurring in a series of 1-aryl-2,2-dimethylindanols, by dynamic NMR. When the aryl moiety is a mesityl or a 2-methyl-1-naphthyl, the rotational barrier exceeds the 25 kcal/mol, so that stable atropisomers are observed. In two cases, all the chiral-atropisomeric species have been separated by enantioselective HPLC, and the comparison between theoretical and experimental electronic circular dichroism spectra allowed the absolute configuration assignment of all the isolated species to be obtained.