The last decade has witnessed a burgeoning of new methods for the enantioselective vicinal difunctionalization of alkenes initiated by electrophilic sulfenyl group transfer. The addition of sulfenium ions to alkenes results in the generation of chiral, non‐racemic thiiranium ions. These highly reactive intermediates are susceptible to attack by a myriad of nucleophiles in a stereospecific ring‐opening event to afford anti 1,2‐sulfenofunctionalized products. The practical application of sulfenium ion transfer has been enabled by advances in the field of Lewis base catalysis. This Review will chronicle the initial discovery and characterization of thiiranium ion intermediates followed by the determination of their configurational stability and the challenges of developing enantioselective variants. Once the framework for the reactivity and stability of thiiranium ions has been established, a critical analysis of pioneering studies will be presented. Finally, a comprehensive discussion of modern synthetic applications will be categorized around the type of nucleophile employed for sulfenofunctionalization.

A catalytic, enantioselective method for the preparation of chiral, non-racemic, alkylboronic esters bearing two vicinal stereogenic centers is described. The reaction proceeds via a 1,2-migration of a zwitterionic thiiranium–boronate complex to give exclusively anti carbosulfenylation products. A broad scope of aryl groups migrate with good yield and excellent enantioselectivity (up to 99:1 e.r.). Similarly, a range of di- and trisubstituted alkenylboronic esters are competent reaction partners. This method provides access to both secondary and tertiary chiral alkylboronic esters.

A method for the catalytic, enantioselective, intramolecular, 1,2-sulfenoamidation of alkenes is described. Lewis base activation of a suitable sulfur electrophile generates an enantioenriched, thiiranium ion intermediate from a β,γ-unsaturated sulfonyl carboxamide. This intermediate is subsequently intercepted by the sulfonamide nitrogen resulting in cyclization to form γ-lactams. Electron-poor alkenes required the use of a new selenophosphoramidate Lewis base catalyst. Subsequent manipulations of the products harness the latent reactivity of both the amide and thioether functionality.

A method for the enantioselective, Lewis base-catalyzed sulfenofunctionalization of cyclic and (Z)-alkenes is reported. The intermediate thiiranium ion generated in the presence of a selenophosphoramide catalyst is intercepted by a variety of nucleophiles. A diverse array of inter- and intramolecular functionalizations proceed in high yield and good to high enantioselectivity (86:14–98:2 er). Prior experimental and computational studies indicated such enantiotopic face discrimination to be poor; however, the results disclosed herein remediate the previous findings. Control experiments were performed to investigate the different behavior of (Z)-alkenes and their more established (E)-counterparts.

Madison mit Arbeiten zur oxidativenDehydrierungl eichter Kohlenwasserstoffe (Gruppe von Ive Hermans). 2017 schloss er sich der Gruppe von S. Denmark an, um enantioselektive Lewis-Base-katalysierte Sulfeniumionentransferprozese zu untersuchen. Scott E. Denmark erhielt 1975 seinen S.B. am MIT und 1980 seinen D.Sc.Tech an der ETH Zürich bei Albert Eschenmoser.Im selben Jahr begann er seine unabhängige Laufbahn an der University of Illinois, und seit 1991 ist er der Reynold C. Fuson Professor of Chemistry.Seine Forschungsinteressen gelten der Entwicklung neuer Synthesen, der explorativen Organoelementchemieu nd dem Ursprung der Stereokontrolle in CC -Bindungsbildungsprozessen.