Unified metal-free intermolecular Heck-type sulfonylation, cyanation, amination, amidation of alkenes by thianthrenation

Abstract

Direct and site-selective C-H functionalization of alkenes under environmentally benign conditions represents a useful and attractive yet challenging transformation to access value-added molecules. Herein, a unified protocol for a variety of intermolecular Heck-type functionalizations of Csp2-H bond of alkenes has been developed by thianthrenation. The reaction features metal-free and operationally simple conditions for exclusive cine-selective C-H functionalization of aliphatic and aryl alkenes to forge C-C, C-N, C-P, and C-S bonds at room temperature, providing a general protocol for intermolecular Heck-type reaction of alkenes with nucleophiles (Nu = sulfinates, cyanides, amines, amides). Alkenes undergo cine-sulfonylation, cyanation, amination to afford alkenyl sulfones, alkenyl nitriles and enamines.

Dielectrophilic Approach to Sequential Heterofunctionalization of Ethylene from Vinylthianthrenium Salt

“…Following previous reports, [15,20,21,24,27] a plausible mechanism for the reaction is proposed (Figure 2). Initially, the pronucleophile 2-alkyl-1,3-ketoester undergoes deprotonation in presence of the carbonate anion.…”

“…[14] These compounds were silylated or borylated by coppercatalyzed reactions [19] and used in the Heck-type reaction with different nucleophiles for the formation of CÀ C, CÀ N, CÀ P, and CÀ S bonds. [20] Furthermore, alkenyl thianthrenium salts were employed in the metal-free allylic CÀ H nitrogenation, oxygenation, and carbonation of alkenes. [21] Recently, Soós developed a Kornblum/Ganem-like oxidation method using alkenyl thianthrenium salts to obtain α,β-unsaturated carbonyl compounds.…”

C(sp3)–H sulfinylation of light hydrocarbons with sulfur dioxide via hydrogen atom transfer photocatalysis in flow

“…The Michael addition reaction of ethane sulfinate intermediate with N -phenyl succinimide resulted in the formation of imide 30 in 56% yield. A cine -sulfonylation reaction was applied for the synthesis of highly electrophilic alkenyl sulfone 31 with a yield of 70% 36 . A two-step procedure was utilized for the synthesis of sulfonamides and sulfonate esters, involving a sulfonyl halide intermediate, leading to medicinally relevant compounds 32–36 , including derivatizations of Amoxapine and (+)-Leelamine.…”

Mechanism of Z-Selective Allylic Functionalization via Thianthrenium Salts

“…These KIEs are inconsistent with rate-determining conjugate-addition-type mechanisms, which have been observed with alkenylthianthrenium salts in other contexts (see the Supporting Information). , To probe the irreversibility of allylic deprotonation, the reaction was conducted with an excess of deuterium oxide as a deuterium source (Scheme B). , We reasoned that irreversible allylic deprotonation would give no deuterium incorporation into the alkenyl position of the allylic amine product. Experimentally, no deuterium was detected in the site of the initial C­(sp 3 )–H bond breaking, which is consistent with the allylic deprotonation being irreversible in the presence of a nucleophile (Scheme B).…”