23033-65-0Relevant articles and documents
Tandem intramolecular carbolithiation-transmetallation: From lithium to copper or boron chemistry
Ortiz, Rosa,Yus, Miguel
, p. 1699 - 1707 (2005)
Lithium/copper transmetallation from the organolithium intermediate 3 (obtained via intramolecular carbolithiation of the acyclic organolithium 2, generated by a chlorine-lithium exchange) gives the corresponding organocopper intermediate 5. This intermediate reacts with eletrophiles, such as allylic or propargylic halides, acyl chlorides or α,β-unsaturated carbonyl compounds giving the expected compounds 6-10, which are not possible to be obtained directly from the organolithium 3. On the other hand, lithium/boron transmetallation affords the corresponding alkylboronic acid 11 which, after palladium-catalysed Suzuki-Miyaura cross-coupling reaction with different aryl bromides gives the expected products 12 with modest yields, the corresponding Ullman biarylic homocoupling products being the major by-products.
Using the Thiyl Radical for Aliphatic Hydrogen-Atom Transfer: Thiolation of Unactivated C?H Bonds
Panferova, Liubov I.,Zubkov, Mikhail O.,Kokorekin, Vladimir A.,Levin, Vitalij V.,Dilman, Alexander D.
supporting information, p. 2849 - 2854 (2020/12/17)
A metal- and catalyst-free thiyl-radical-mediated activation of alkanes is described. Tetrafluoropyridinyl disulfide is used to perform thiolation of the C?H bonds under irradiation with 400 nm light-emitting diodes. The key C?H activation step is believed to proceed via hydrogen-atom abstraction effected by the fluorinated thiyl radical. Secondary, tertiary, and heteroatom-substituted C?H bonds can be involved in the thiolation reaction. The resulting sulfides have wide potential as photoredox-active radical precursors in reactions with alkenes and heteroarenes.
Photoredox Reaction of 2-Mercaptothiazolinium Salts with Silyl Enol Ethers
Zemtsov, Artem A.,Ashirbaev, Salavat S.,Levin, Vitalij V.,Kokorekin, Vladimir A.,Korlyukov, Alexander A.,Dilman, Alexander D.
, (2019/11/29)
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.
Cu/Mn bimetallic catalysis enables carbonylative Suzuki-Miyaura coupling with unactivated alkyl electrophiles
Pye, Dominic R.,Cheng, Li-Jie,Mankad, Neal P.
, p. 4750 - 4755 (2017/07/10)
A bimetallic system consisting of Cu-carbene and Mn-carbonyl co-catalysts was employed for carbonylative C-C coupling of arylboronic esters with alkyl halides, allowing for the convergent synthesis of ketones. The system operates under mild conditions and exhibits complementary reactivity to Pd catalysis. The method is compatible with a wide range of arylboronic ester nucleophiles and proceeds smoothly for both primary and secondary alkyl iodide electrophiles. Preliminary mechanistic experiments corroborate a hypothetical catalytic mechanism consisting of co-dependent cycles wherein the Cu-carbene co-catalyst engages in transmetallation to generate an organocopper nucleophile, while the Mn-carbonyl co-catalyst activates the alkyl halide electrophile by single-electron transfer and then undergoes reversible carbonylation to generate an acylmanganese electrophile. The two cycles then intersect with a heterobimetallic, product-releasing C-C coupling step.
