Diastereoselective Synthesis of Substituted Tetrahydrothiopyrans via (3,5)-Thionium–Ene Cyclization Reaction

Abstract

Tetrahydrothiopyrans have been efficiently synthesized in good yields with excellent diastereoselectivity from aldehydes and substituted 5-methylhex-4-ene-1-thiol via (3,5)-thionium-ene cyclization reaction mediated by boron trifluoride etherate.

Sensing during In Situ Growth of Mn‐Doped ZnS QDs: A Phosphorescent Sensor for Detection of H2S in Biological Samples

“…In continuation of our interest in the synthesis of heterocyclic compounds through the ene‐cyclization reaction,12,13 we searched for a methodology for the synthesis of substituted piperidines. We envisioned that the reaction between 4‐methyl‐ N ‐(5‐methylhex‐4‐en‐1‐yl)benzenesulfonamide ( 1 ) and aldehyde 2 in the presence of a Lewis acid would provide access to 2,3‐disubstituted piperidines 4 through an intramolecular iminium‐ene cyclization reaction (see Scheme ).…”

“…The imino‐ene reaction has been used for the synthesis of homoallylic amines9 as well as the synthesis of benzimidazole10 and thiazolidines 11. Recently, we prepared oxygen12 and sulfur13 heterocycles by using the oxonium‐ene and thionium‐ene cyclization reaction, respectively. Herein, we report a methodology for the synthesis of tetrahydroquinolines.…”

Emerging Organosulfonium Electrophiles as Unique Reagents for Carbon–Sulfur Bond Formation: Prospects in Synthetic Chemistry of Organosulfur Compounds

“…40 Another type of the sulfur-containing cationic reagent is a thionium cation (R=S + -R), which mediated the reaction to synthesize substituted tetrahydropyrans via thionium-ene cyclization (Scheme 11). 41 Sulfonium ions have much larger varieties than oxonium ions, giving rise to many types of electrophilic reactions in addition to the above-mentioned reactions utilizing RS + and their equivalents. Different from oxygen, sulfur forms threemembered sulfonium cations RS(RSSR) + from RS + and RSSR.…”

Organocatalytic Asymmetric Synthesis of Tetrahydrothiophenes and Tetrahydrothiopyrans

“…Moreover, the tetrahydrothiopyrans can also be transformed into a variety of valuable structures . Previous methods for metal‐ and Lewis‐acid‐catalyzed tetrahydropyran syntheses are associated with major drawbacks such as lack of enantioselectivity and use of expensive reagents . Therefore, to overcome these limitations it is important to develop efficient methods for the synthesis of enantiopure tetrahydrothiopyrans.…”