Enantioselective Synthesis of Planar-Chiral Sulfur-Containing Cyclophanes by Chiral Sulfide Catalyzed Electrophilic Sulfenylation of Arenes.

An efficient catalytic asymmetric electrophilic sulfenylation reaction for the synthesis of planar-chiral sulfur-containing cyclophanes has been developed for the first time. This was achieved by using a new Lewis base catalyst and a new ortho-trifluoromethyl-substituted sulfenylating reagent. Using the substrates with low rotational energy barrier, the transformation proceeded through a dynamic kinetic resolution, and the high rotational energy barrier of the substrates allowed the reaction to undergo a kinetic resolution process.

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.

Chiral Selenide/Achiral Sulfonic Acid Cocatalyzed Atroposelective Sulfenylation of Biaryl Phenols via a Desymmetrization/Kinetic Resolution Sequence.

Enantioselective synthesis of axially chiral sulfur-containing biaryl derivatives through the electrophilic sulfenylation of biaryl phenols has been achieved for the first time. This catalytic asymmetric system, which involves sequential desymmetrization and kinetic resolution, is enabled by a combination of a novel 3,3'-disubstituted BINOL-derived selenide catalyst and an achiral sulfonic acid. Control experiments and computational studies suggest that multiple noncovalent interactions between the cocatalysts and substrate, especially a network of hydrogen bond interactions, play a crucial role in determining the enantioselectivity and reactivity.

Selenium-Catalyzed Trifluoromethylsulfinylation/Rearrangement of Allylic and Propargylic Alcohols: Access to Allylic and Allenic Triflones.

A selenium-catalyzed trifluoromethylsulfinylation/rearrangement of allylic and propargylic alcohols for synthesizing triflones was developed for the first time. Various allylic and allenic triflones were delivered in moderate to excellent yields. After numerous control experiments were performed, it was suggested that this transformation includes an unusual [SCF] group disproportionation process that forms [SOCF] that is in-situ-catalyzed by selenium, and HO was used as an oxygen source.

Divergent Synthesis of Trifluoromethyl Sulfoxides and β-SCF Carbonyl Compounds by Tandem Trifluoromethylthiolation/Rearrangement of Allylic and Propargylic Alcohols.

A selenium-catalyzed trifluoromethylthiolation/[2,3]-sigmatropic rearrangement of tertiary allylic and propargylic alcohols which could provide straightforward and facile access to trifluoromethyl sulfoxides was developed. Various allylic and allenic trifluoromethyl sulfoxides were obtained with moderate to excellent yields. Meanwhile, a Lewis acid mediated trifluoromethylthiolation/1,2-rearrangement to synthesize β-SCF carbonyl compounds was also accomplished.

Lewis Base/Brønsted Acid Co-Catalyzed Asymmetric Thiolation of Alkenes with Acid-Controlled Divergent Regioselectivity.

A divergent strategy for the facile preparation of various enantioenriched phenylthio-substituted lactones was developed based on Lewis base/Brønsted acid co-catalyzed thiolation of homoallylic acids. The acid-controlled regiodivergent cyclization (6-endo vs. 5-exo) and acid-mediated stereoselective rearrangement of phenylthio-substituted lactones were explored.

Lewis base-catalyzed asymmetric sulfenylation of alkenes: construction of sulfenylated lactones and application to the formal syntheses of (-)-nicotlactone B and (-)-galbacin.

An efficient method for the preparation of chiral sulfenylated lactones has been described based on Lewis base-catalyzed enantioselective sulfenylation of unsaturated carboxylic acids. The scope of this method includes two enantioselective cyclization reactions: 5-endo and 6-exo thiolactonizations of alkenes. Two types of lactones were obtained with up to 95% ee and 99% yield.

Lewis Base/Brønsted Acid Co-catalyzed Enantioselective Sulfenylation/Semipinacol Rearrangement of Di- and Trisubstituted Allylic Alcohols.

An enantioselective sulfenylation/semipinacol rearrangement of 1,1-disubstituted and trisubstituted allylic alcohols was accomplished with a chiral Lewis base and a chiral Brønsted acid as cocatalysts, generating various β-arylthio ketones bearing an all-carbon quaternary center in moderate to excellent yields and excellent enantioselectivities. These chiral arylthio ketone products are common intermediates with many applications, for example, in the design of new chiral catalysts/ligands and the total synthesis of natural products. Computational studies (DFT calculations) were carried out to explain the enantioselectivity and the role of the chiral Brønsted acid.

TMSCl-Catalyzed Electrophilic Thiocyano Oxyfunctionalization of Alkenes Using N-Thiocyano-dibenzenesulfonimide.

Numerous electrophilic thiocyano oxyfunctionalization reactions of alkenes have been achieved using N-thiocyano-dibenzenesulfonimide, which is a new electrophilic thiocyanation reagent and could be easily prepared in two steps from dibenzenesulfonimide. This approach provides efficient, simple, and modular methods for the formation of SCN-containing heterocycles such as lactones, tetrahydrofurans, dihydrofurans, and dihydrobenzofurans in moderate to excellent yields. Meanwhile, diverse oxa-quaternary centers were rapidly constructed.