Hydrothiolation Of Alkenes Research Articles

Photoredox Reaction of 2-Mercaptothiazolinium Salts with Silyl Enol Ethers.

A method for the generation of free radicals from thiazolinium salts upon photocatalytic reduction is described. The thiazolinium salts are generated by treatment with methyl triflate of 2-mercaptothiazolines, which can be readily obtained from alkyl bromides and tosylates via a nucleophilic substitution reaction or by hydrothiolation of alkenes. Silyl enol ethers were used to trap the radicals, furnishing ketones after successive single-electron oxidation and elimination of the silyl cation.

Sulfamic acid: An efficient and recyclable catalyst for the regioselective hydrothiolation of terminal alkenes and alkynes with thiols

Herein, we described a new method for the preparation of thioethers through hydrothiolation of alkenes and alkynes, using sulfamic acid as a reusable catalyst. Generally, this new methodology afforded the desired products in very good yields, under metal and solvent-free conditions. Furthermore, the catalyst was easily recovered and reused for further catalytic reactions without loss of activity.

Hydrothiolation of Alkenes and Alkynes Catalyzed by 3,4‐Dimethyl‐5‐vinylthiazolium iodide and Poly(3,4‐dimethyl‐5‐vinylthiazolium) iodide

AbstractThe highly selective anti‐Markovnikov addition of thiols to unactivated alkenes and alkynes was demonstrated by using 3,4‐dimethyl‐5‐vinylthiazolium iodide or its polymer, poly(3,4‐dimethyl‐5‐vinylthiazolium) iodide, as a complementary catalyst. The reaction proceeded cleanly under base‐free conditions in air with both aromatic and aliphatic thiols. The polymer catalyst showed a high turnover number (≈5800) and could be reused up to four times without any loss of catalytic activity. DFT calculations supported stabilization of the thiyl radical intermediate by the thiazolium cation, which resulted in reaction of the radical with unsaturated C−C bonds.

Synthesis of S-Linked N-Acetylneuraminic Acid Derivatives via Photoinduced Thiol-ene and Thiol-yne Couplings

Thio-linked mono- and bivalent mimetics of α(2→3) and α(2→6)-linked sialosides were prepared by photoinduced hydrothiolation of alkenes and alkynes with the 2-mercapto sialic acid. Thiosialylation of 6-O-allyl- or 3-O-allyl-substituted galactose derivatives has been carried out by the thiol–ene click reaction. Double thiosialylation has also been achieved via thiol–yne chemistry using propargylated galactose derivatives as the alkyne components and the peracetylated 2-mercapto sialic acid as the thiol.