Syntheses and crystal structures of two dinaphtho[2,1-d:1′,2′-f][1,3]dithiepine atropisomers

Abstract

The closely related title compounds, 1-(dinaphtho[2,1-d:1′,2′-f][1,3]dithiepin-4-yl)-2,2-dimethylpropan-1-ol, C26H24OS2, 1 and 2-(dinaphtho[2,1-d:1′,2′-f][1,3]dithiepin-4-yl)-3,3-dimethylbutan-2-ol, C27H26OS2, 2, both comprise an atropisomeric binaphthyl dithioacetal unit substituted at the methylene carbon atom with a chiral neopentyl alcohol grouping. The overall stereochemistry of the racemate in each case is defined as aS,R and aR,S. In 1, the hydroxyl group generates inversion dimers via pairwise intermolecular O—H...S hydrogen bonds whereas in 2, the O—H...S link is intramolecular. Weak C—H...π interactions link the molecules into extended arrays in both structures.

Keywords

• crystal structure
• atropisomer
• binaphthalene dithiol
• asymmetric synthesis
• hydrogen bonds
• c—h...π contacts