Extraordinary behavior of β-hydroxy sulfoxides and sulfone of pinane series

GRAPHICAL ABSTRACT

ABSTRACT

The “racemic compound-like” behavior, low-temperature conformational rearrangement and “crystallization-induced diastereomerization” of β-hydroxysulfoxides and sulfone of pinane series have been studied. It was established, that the sample of sulfoxide crystallizes as an asymmetric dimer containing a supramolecularcentro-symmetric moiety formed through S=O···H‒O interactions between two independent molecules. Moreover, it was found that this dimer can crystallize in two so-called “packing polymorphs”—monoclinic and triclinic ones. By transition from the room temperature to 150 К for both polymorphic forms conformational restructuring of a stable hydrogen-bonded synthon from “unfolded” form to “folded” one has been observed. The sample of sulfoxide is interesting as the first example of the co-crystallization of chiral sulfur compounds. Surprisingly we have found a similar H-bonded dimer, formed by independent molecules, where all sulfone molecules are identical in stereochemical aspect. We suggested to use the new term “crystallization-induced diastereomerization” for the description of the stereochemical process leading to the formation of sulfone dimer. From a supramolecular chemistry point of view, we can speak of the finding of a new robust and reproducible synthon. From a stereochemical point of view, an “enantiophilic” fragment was discovered—a β-hydroxysulfoxide or sulfone group, capable of recognizing its mirror image.

KEYWORDS:

• β-Hydroxysulfoxide
• β-hydroxysulfone
• (−)-β-pinene
• “racemic compound-like” crystallization
• polymorphic modifications
• crystallization-induced diastereomerization

Funding

The work was performed using a subsidy under state support of KFU for increasing the competitiveness of leading global science-education centers.