17475-11-5Relevant academic research and scientific papers
Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
Luo, Xiaosheng,Wang, Ping
, p. 4960 - 4965 (2021/07/20)
Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
Enantioselective Rh(II)-Catalyzed Desymmetric Cycloisomerization of Diynes: Constructing Furan-Fused Dihydropiperidines with an Alkyne-Substituted Aza-Quaternary Stereocenter
Cao, Tongxiang,Chen, Kai,Lu, Jiajun,Ma, Jun,Wu, Rui,Zhu, Shifa
supporting information, p. 14916 - 14925 (2021/09/18)
Described herein is an enantioselective dirhodium(II)-catalyzed cycloisomerization of diynes achieved by the strategy of desymmetrization, which not only represents a new cycloisomerization reaction of diynes but also constitutes the first Rh(II)-catalyzed asymmetric intramolecular cycloisomerization of 1,6-diynes. This protocol provides a range of valuable furan-fused dihydropiperidine derivatives with an enantiomerically enriched alkynyl-substituted aza-quaternary stereocenter in high efficiency, complete atom economy, and excellent enantioselectivity (up to 98% ee). Besides, the highly functionalized products could be easily transformed into various synthetically useful building blocks and conjugated with a series of pharmaceutical molecules. The mechanism involving a concerted [3+2] cycloaddition/[1,2]-H shift of the Rh(II) carbenoid intermediate was elucidated by DFT calculations and mechanistic studies. More importantly, the first single crystal of alkyne-dirhodium(II) was obtained to show that a η2-coordinating activation of alkynal by dirhodium(II) was involved. Weak hydrogen bondings between the carboxylate ligands and alkynal were found, which probably made the well-defined paddlewheel-like dirhodium(II) distinctive from other metal complexes in catalyzing this transformation. Furthermore, the origin of the enantioselectivity was elucidated by a Rh2(R-PTAD)4-alkyne complex and additional calculational studies.
Sc(OTf)3-catalyzed [3 + 2]-cycloaddition of nitrones with ynones
He, Chun-Ting,Han, Xiao-Li,Zhang, Yan-Xue,Du, Zhen-Ting,Si, Chang-Mei,Wei, Bang-Guo
supporting information, p. 457 - 466 (2021/01/29)
An efficient approach to access functionalized (2,3-dihydroisoxazol-4-yl) ketones has been developed by reacting nitrones 4 with ynones 7 or terminal ynones 10 in a one-pot fashion. The reaction went through a formal Sc(OTf)3-catalyzed [3 + 2]-cycloaddition process to generate a number of functionalized (2,3-dihydroisoxazol-4-yl) ketones 11aa-11aw, 11ba-11la and 12aa-12ae in moderate to good yields. This journal is
Ionic liquid-mediated benzoyl transfer-coupling in the Suzuki and Sonogashira reactions and aryl transfer-coupling by decarbonylative Heck reaction, using N-Benzoyl-saccharin (NBSac) as reagent
Malunavar, Shruti S.,Sutar, Suraj M.,Prabhala, Pavankumar,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
, (2020/05/18)
The efficacy of N-benzoyl-saccharin (NBSac) as reagent for selective benzoyl transfer-coupling in the Suzuki reaction in BMIM-IL/[PAIM][NTf2] as solvent/base, and in the Sonogashira reaction employing guanidinium-IL (GIL) as solvent, are demonstrated. Decarbonylative aryl transfer-coupling occurs in the Heck reaction employing GIL as solvent. The reactions are catalyzed by Pd(OAc)2 or NiCl2(dppp), are performed under mild conditions in good yields, and have the potential for recycling/reuse of the IL solvent. Collectively, these methods provide facile access to diverse libraries of diarylketones, keto-ethynes and diaryl-ethenes.
Visible-light-mediated photocatalytic cross-coupling of acetenyl ketones with benzyl trifluoroborate
Zhang, Lingchun,Chu, Yanle,Ma, Peizhi,Zhao, Shujuan,Li, Qiaoyan,Chen, Boya,Hong, Xuejiao,Sun, Jun
supporting information, p. 1073 - 1077 (2020/02/22)
In this report, we describe a simple visible light-triggered Barbier-type reaction by employing acetenyl ketones with benzyl trifluoroborates. Through a radical-radical cross-coupling process, this photocatalytic protocol furnished a wide range of tertiary propargyl alcohols. Mechanistic investigation indicated that proton-coupled electron transfer (PCET) might be involved in the photochemical transformations.
Iron(III) chloride-promoted cyclization of α,-alkynic tosylhydrazones with diselenides: Synthesis of 4-(arylselanyl)-1: H-pyrazoles
Ji, Shun-Jun,Li, Fang-Hui,Li, Jian,Wang, Shun-Yi,Yao, Hai-Feng
supporting information, p. 1987 - 1993 (2020/03/23)
A highly efficient iron(iii) chloride-promoted cyclization between α,-alkynic tosylhydrazones and diselenides to form a 4-(arylselanyl)-1H-pyrazole skeleton is studied. This reaction forms C-N and C-Se bonds in one step by utilizing inexpensive iron(iii) chloride instead of expensive transition metal additives. This strategy features easily synthesized substrates, mild reaction conditions and high tolerance to functional groups.
Palladium-Catalyzed Oxidative C≡C Triple Bond Cleavage of 2-Alkynyl Carbonyl Compounds Toward 1,2-Dicarbonyl Compounds?
Hu, Ming,Li, Jin-Heng,Luo, Mu-Jia,Zhou, Ming-Bo
supporting information, p. 553 - 558 (2020/04/20)
A new, general palladium-catalyzed oxidative strategy for the cleavage of the C≡C triple bond is presented. By employing PdCl2, CuBr2, TEMPO and air as the catalytic system and H2O as the carbonyl oxygen atom source, a wide range of 2-alkynyl carbonyl compounds, including 1,3-disubstituted prop-2-yn-1-ones, propiolamides and propiolates, lost an alkynyl carbon to access various 1,2-dicarbonyl compounds, e.g., 1,2-diones, 2-keto amides and 2-keto esters, through Wacker oxidation, intramolecular cyclization and C—C bond cleavage cascades.
Synthesis of C4-alkynylisoxazoles: Via a Pd-catalyzed Sonogashira cross-coupling reaction
Yang, Wen,Yao, Yongqi,Yang, Xin,Deng, Yingying,Lin, Qifu,Yang, Dingqiao
, p. 8894 - 8904 (2019/03/28)
A Pd-catalyzed Sonogashira cross-coupling reaction for the synthesis of C4-alkynylisoxazoles from 3,5-disubsitituted-4-iodoisoxazoles and terminal alkynes was described, which could afford the corresponding products with high yield (up to 98%). The result
Synthesis of 1-Cyano-3-acylnaphthalenes via Formal [4+2] Benzannulation of 2-(2-Alkynylphenyl)acetonitriles and Alkynones
Chen, Lu-Lu,Zhang, Jing-Wen,Yang, Wan-Wan,Fu, Ji-Ya,Zhu, Jun-Yan,Wang, Yan-Bo
, p. 8090 - 8099 (2019/06/27)
Effective transition-metal-free formal [4+2] benzannulation for the preparation of 1-cyano-3-acylnaphthalenes from 2-(2-alkynylphenyl)acetonitriles and alkynones through sequential C-C bond coupling has been developed. This protocol is characterized by mi
Base-Controlled Divergent Synthesis of 5-Cyanobenzoxepines and Benzofuro[2,3- b]pyridines from 2-Bromophenylacetonitriles and Ynones
Chen, Lu-Lu,Zhang, Jing-Wen,Chen, Pei,Zhang, Shuai,Yang, Wan-Wan,Fu, Ji-Ya,Zhu, Jun-Yan,Wang, Yan-Bo
supporting information, p. 5457 - 5461 (2019/08/01)
An effective base-controlled divergent annulation reaction of 2-bromophenylacetonitriles and ynones has been developed. Various functionalized 5-cyanobenzoxepines and benzofuro[2,3-b]pyridines were obtained with a broad substrate scope and high regioselec
