Catalyst Control over Threefold Stereogenicity: Selective Synthesis of Atropisomeric Sulfones with Stereogenic C-S Axes.

Catalyst control over higher-order stereogenicity addresses significantly extended stereochemical space, but selective methods to govern threefold stereogenic units remained elusive. Herein, we report the stereoselective synthesis of threefold stereogenic triptycyl sulfones with atropisomerism arising from a C(sp )-S bond. An oxidation of a stereodynamic thioether controlled by a chiral phosphoric acid catalyst allowed selective access to enantioenriched triptycyl sulfoxides.

o-Quinodimethane Atropisomers: Enantioselective Synthesis and Stereospecific Transformation.

o-Quinodimethanes have remarkable utility as reactive intermediates in Diels-Alder reactions, enabling significantly accelerated routes to complex polycyclic compounds. The discovery of different discrete precursors to thermally generate o-quinodimethanes thereby greatly augmented their availability and versatility. However, due to the required high temperatures and the immense reactivity of o-quinodimethanes, stereoselectivity to afford isomerically defined products still constitutes a critical challenge.