Crystal structure of 2α-(1,1-diphenylethyl)-4-methyl-4α,5α-diphenyl-1,3-dioxolane: the result of a non-acid pinacol rearrangement

Abstract

The title compound, C30H28O2, was obtained during recrystallization of (±)-1,2-diphenyl-1,2-propanediol in 1-butanol, from an unexpected non-acid-catalyzed pinacol rearrangement followed by acetal formation of the newly formed aldehyde with the diol. The tri-substituted dioxolane ring has a twist conformation on the C—O bond opposite the methyl-substituted C atom. There is an intramolecular C—H...π interaction present involving one of the diphenylethyl rings and an H atom of the phenyl ring in position 4 of the dioxolane ring. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming chains along [001]. The chains are linked by a second C—H...π interaction, forming sheets parallel to the bc plane.

Keywords

• crystal structure
• 1,3-dioxolane
• non-acid-catalyzed pinacol rearrangement
• acetal
• C—H...O hydrogen bonds
• C—H...π interactions
• density functional analysis.