Atroposelective Electrophilic Sulfenylation of N‐Aryl Aminoquinone Derivatives Catalyzed by Chiral SPINOL‐Derived Sulfide.

Atroposelective electrophilic sulfenylation of N‐aryl aminoquinone derivatives has been achieved for the first time. This transformation is enabled by a new chiral 6,6′‐disubstituted SPINOL‐derived sulfide catalyst, which was first synthesized and then successfully explored for catalyzing enantioselective reactions. Various axially chiral sulfur‐containing diarylamine derivatives were readily obtained in moderate to excellent yields with moderate to excellent enantioselectivities. A class of relatively flexible stereogenic C−N axes was easily constructed. The experimental results and a computational study suggested that an intramolecular N−H⋅⋅⋅S hydrogen bond is important for the stability of the C−N axis, which is consistent with our hypothesis. Density functional theory calculations revealed the origin of atroposelectivity and underscored the importance of catalyst rigidity in this sulfenylation reaction. [ABSTRACT FROM AUTHOR]