Electrophilic Selenium-Catalyzed Desymmetrizing Cyclization to Access P-Stereogenic Heterocycles

Abstract

The construction of phosphorus stereocenters under metal-free conditions remains a formidable challenge. Herein, we report a mechanistically distinct chiral electrophilic selenium catalysis-enabled desymmetrizing cyclization to access valuable chiral phosphorus-stereogenic heterocycles with high efficiency. This ambient temperature method affords a broad range of chiral phosphorus compounds that bear a phenolic hydroxyl group as a useful synthetic handle and, thus, enriches the toolbox for rapid generation of molecular complexity. The control experiments and DFT calculations indicate that the dual-hydrogen-bonding bridge formed between the substrate and TfO − anion plays a crucial role in determining the enantioselectivity of the transformation.

Asymmetric Photoaerobic Lactonization and Aza-Wacker Cyclization of Alkenes Enabled by Ternary Selenium–Sulfur Multicatalysis

“…From preliminary work on photoaerobic lactonizations, we realized that the degree of stereoinduction of a given chiral selenium-π-acid roughly correlated with its conformational rigidity . This notion is in good agreement with very insightful reports by Maruoka et al, Denmark et al, and others on thermal selenium-π-acid-catalyzed alkene functionalizations .…”

“…Furthermore, selenium-π-acids interact with their olefinic substrates through dynamic covalent binding to the carbon–carbon π-bond (Scheme f), which opens the opportunity to induce stereochemical information by means of chiral selenium species under photocatalytic conditions. However, previous efforts in this direction only met with limited success, leading to average er values distinctly below 75:25. , As a viable solution to previously encountered difficulties, we now report the design of a modular, spirocyclic selenium-π-acid motif, which allows for the photocatalytic, enantioselective lactonization and amination of nondirecting, internal alkenes under the assistance of sulfur cocatalysts to provide access to various chiral alkenolides and for the first time 3-pyrrolines.…”

Enantioselective cross-dehydrogenative coupling enabled by organocatalysis

“…343–346 Very recently, Yang group reported an intramolecular desymmetrizing cyclization approach to access chiral P-stereogenic heterocycles by electrophilic selenium catalysis (Scheme 68). 347 The reaction was carried out using diselenide catalyst C51 containing six-membered tetrahydronaphthalen-1-ol backbone with a sterically hindered SiPh 2 t Bu group in the presence of 1-fluoropyridiniumtriflate as the oxidant, delivering a broad range of P-stereogenic heterocycles bearing a phenolic hydroxyl group in good to excellent yields (64–98%) and enantioselectivities (80–99%). Mechanistically speaking, the oxidation of the chiral diselenide catalyst C51 leads to the formation of catalytic active R*SeX species.…”

Rh(III)-Catalyzed Atroposelective C–H Selenylation of 1-Aryl Isoquinolines

“…In this regard, a wide variety of chiral selenium catalysts have been developed for asymmetric transformations in organic synthesis (Figure ). , Among them, organoselenide-catalyzed asymmetric functionalization of alkene and intramolecular cyclization of alkene are the most representative transformations . Therefore, the development of efficient approaches for the construction of chiral organoselenides always attracts considerable attention because of their importance in the field of organic synthesis.…”