15288-74-1Relevant academic research and scientific papers
A visible-light mediated ring opening reaction of alkylidenecyclopropanes for the generation of homopropargyl radicals
Mao, Ben,Ning, Chao,Shi, Min,Wei, Yin,Zhang, Xiao-Yu
, p. 9088 - 9095 (2021)
Classical cyclopropylcarbinyl radical clock reactions have been widely applied to conduct mechanistic studies for probing radical processes for a long time; however, alkylidenecyclopropanes, which have a similar molecular structure to methylcyclopropanes, surprisingly have not yet attracted researcher's attention for similar ring opening radical clock processes. In recent years, photocatalytic NHPI ester activation chemistry has witnessed significant blooming developments and provided new synthetic routes for cross-coupling reactions. Herein, we wish to report a non-classical ring opening radical clock reaction using innovative NHPI esters bearing alkylidenecyclopropanes upon photoredox catalysis, providing a brand-new synthetic approach for the direct preparation of a variety of alkynyl derivatives. The potential synthetic utility of this protocol is demonstrated in the diverse transformations and facile synthesis of bioactive molecules or their derivatives and medicinal substances.
Photocatalytic decarboxylative alkylations mediated by triphenylphosphine and sodium iodide
Fu, Ming-Chen,Shang, Rui,Zhao, Bin,Wang, Bing,Fu, Yao
, p. 1429 - 1434 (2019/04/30)
Most photoredox catalysts in current use are precious metal complexes or synthetically elaborate organic dyes, the cost of which can impede their application for large-scale industrial processes. We found that a combination of triphenylphosphine and sodium iodide under 456-nanometer irradiation by blue light–emitting diodes can catalyze the alkylation of silyl enol ethers by decarboxylative coupling with redox-active esters in the absence of transition metals. Deaminative alkylation using Katritzky’s N-alkylpyridinium salts and trifluoromethylation using Togni’s reagent are also demonstrated. Moreover, the phosphine/iodide-based photoredox system catalyzes Minisci-type alkylation of N-heterocycles and can operate in tandem with chiral phosphoric acids to achieve high enantioselectivity in this reaction.
Photoredox-Catalyzed Decarboxylative Alkylation of Silyl Enol Ethers to Synthesize Functionalized Aryl Alkyl Ketones
Kong, Weiguang,Yu, Changjiang,An, Hejun,Song, Qiuling
, p. 349 - 352 (2018/01/28)
Photoredox-catalyzed decarboxylative alkylation of silyl enol ethers has been developed. Diverse functionalized aryl alkyl ketones were afforded in modest to good yields using N-(acyloxy)phthalimide as an easy access alkyl radical source under mild and operationally simple conditions. The excellent performance of drug molecules such as fenbufen and indomethacin and naturally occurring carboxylic acids such as stearic acid and dehydrocholic acid further demonstrated the practicability of the reaction.
Stereoselective Radical Cyclization Cascades Triggered by Addition of Diverse Radicals to Alkynes to Construct 6(5)-6-5 Fused Rings
Huang, Lin,Ye, Liu,Li, Xiao-Hua,Li, Zhong-Liang,Lin, Jin-Shun,Liu, Xin-Yuan
, p. 5284 - 5287 (2016/10/31)
Cascade radical cyclization of alkynyl ketones with various carbon- and heteroatom-centered radical precursors via a sequential radical addition/1,5-H radical shift/5-exo-trig/radical cyclization process was realized for the first time. This method provides a strategically novel and step-economical protocol for diversity-oriented synthesis of a wide range of carbocyclic and heterocyclic 6(5)-6-5 fused ring systems with three contiguous stereocenters, including a quaternary carbon in high yields with excellent chemo- and diastereoselectivity.
Stereoselective synthesis of medium-sized cyclic compounds through the intramolecular michael-type reaction utilizing alkyne-hexacarbonyldicobalt complex formation
Inaba, Kennichi,Takaya, Jun,Iwasawa, Nobuharu
, p. 474 - 475 (2008/02/02)
Alkyne-hexacarbonyldicobalt complexes having silyl enol ether and electron-deficient alkene moieties on opposite ends were treated with MeAlCl2 in the presence of 2,6-di-t-butylpyridine in CH 2Cl2 to give synthetically use
Tandem nucleophilic addition/fragmentation reactions and synthetic versatility of vinylogous acyl triflates
Kamijo, Shin,Dudley, Gregory B.
, p. 6499 - 6507 (2007/10/03)
A thorough analysis of the chemistry of vinylogous acyl triflates provides insight into important chemical processes and opens new directions in synthetic technology. Tandem nucleophilic addition/C-C bond cleaving fragmentation reactions of cyclic vinylogous acyl triflates 1 yield a variety of acyclic acetylenic compounds. Full details are disclosed herein. A wide array of nucleophiles, such as organolithium and Grignard reagents, lithium enolates and their analogues, hydride reagents, and lithium amides, are applied. The respective reactions produce ketones 2, 1,3-diketones and their analogues 3, alcohols 4, and amides 5. The present reactions are proposed to proceed through a 1,2-addition of the nucleophile to the carbonyl group of starting triflates 1 to form tetrahedral alkoxide intermediates C, followed by Grob-type fragmentation, which effects C-C bond cleavage to yield acyclic acetylenic compounds 2-5 and 7. The potent nucleofugacity of the triflate moiety is channeled through the σ-bond framework of 1, providing direct access to the fragmentation pathway without denying other typical reactions of cyclic vinylogous esters. The synthetic versatility of vinylogous acyl triflates, including functionalization reactions of the cyclic enone core (1 → 6 or 8), is also illustrated.
A tandem carbanion addition/carbon-carbon bond cleavage yields alkynyl ketones
Kamijo, Shin,Dudley, Gregory B.
, p. 5028 - 5029 (2007/10/03)
Carbanion addition to vinylogous acid triflates triggers carbon-carbon bond cleavage to form alkynyl ketones under mild conditions. Mechanistic factors affecting the cleavage event and its relationship to complementary fragmentations are discussed. A rang
