[6]Saddlequat: a [6]helquat captured on its racemization pathway

Abstract

A dicationic [6]helicene congener captured on the racemization pathway in its saddle-shaped geometry is introduced. Synthesis, structure, resolution, and dynamic properties of this chiral [6]saddlequat in-between and its highly stereocontrolled transformation into enantiopure [6]helquat are discussed and demonstrated. The dynamic aspects established by experiment and supported by detailed DFT-D calculations are presented visually in the form of a movie (electronic table-of-contents and electronic supplementary information). The title [6]saddlequat was found to be an isolable chiral species on the entirely chiral enantiomerization pathway of a [6]helquat that is discussed as an example of Mislow's “rubber glove” molecule.