29805-16-1Relevant academic research and scientific papers
Multisubstituted pyrazole synthesis via [3?+?2] cycloaddition/rearrangement/N[sbnd]H insertion cascade reaction of α-diazoesters and ynones
Feng, Xiaoming,Liu, Xiaohua,Zeng, Zi,Zhao, Peng
, p. 132 - 135 (2020/12/21)
The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)3 as the catalyst are described. A series of 4-substituted pyrazoles were obtained via [3 + 2] cycloaddition, 1,5-ester shift, 1,3-H shift, and N[sbnd]H insertion process. Deuterium labelling experiments, kinetic studies and control experiments were carried out for the rationalization of the mechanism.
Lipase/Oxovanadium Co-Catalyzed Dynamic Kinetic Resolution of Propargyl Alcohols: Competition between Racemization and Rearrangement
Kawanishi, Shinji,Oki, Shinya,Kundu, Dhiman,Akai, Shuji
supporting information, p. 2978 - 2982 (2019/03/26)
Quantitative conversion of racemic propargyl alcohols into optically active propargyl esters with up to 99% ee has been achieved by lipase/oxovanadium co-catalyzed dynamic kinetic resolution, which combines the lipase-catalyzed enantioselective esterification of the racemic substrates and the in situ racemization of the remaining enantiomers. The success is owed to our discovery of a magic solvent, (trifluoromethyl)benzene, that accelerated the racemization while sufficiently suppressing the common oxovanadium-catalyzed rearrangement of propargyl alcohols to irreversibly produce enals.
Palladium-catalyzed [3+2] annulation of allenyl carbinol acetates with C,N-cyclic azomethine imines
Mao, Biming,Zhang, Junya,Xu, Yi,Yan, Zhengyang,Wang, Wei,Wu, Yongjun,Sun, Changqing,Zheng, Bing,Guo, Hongchao
supporting information, p. 12841 - 12844 (2019/11/05)
In this paper, a palladium-catalyzed [3+2] annulation of allenyl carbinol acetates with azomethine imines has successfully been developed under mild reaction conditions, affording biologically interesting tetrahydropyrazoloisoquinoline derivatives in high to excellent yields and with excellent stereoselectivity. The reaction follows a tandem [3+2] cycloaddition/allylation/elimination of AcOH pathway. Allenyl carbinol acetates also reacted well with in situ generated azomethine imine under cocatalysis of Ag(i)/Pd(0) catalysts in a similar reaction pathway.
Cu-Pybox catalyzed synthesis of 2,3-disubstituted imidazo[1,2-a]pyridines from 2-aminopyridines and propargyl alcohol derivatives
Cheng, Cang,Ge, Luo,Lu, Xuehe,Huang, Jianping,Huang, Haocheng,Chen, Jie,Cao, Weiguo,Wu, Xiaoyu
, p. 6866 - 6874 (2016/10/04)
A highly efficient cascade sequence for syntheses of 2,3-disubstituted imidazo[1,2-a]pyridines with exclusive regioselectivity in moderate to excellent yields has been developed. This cascade was initiated through propargylation of 2-aminopyridines at pyridine-nitrogen with propargyl alcohol derivatives using Cu(II)-Pybox as catalyst and followed by an intramolecular cyclization and isomerization. Besides 2-aminopyridine, less reactive 2-aminopyrimidine, 2-aminopyrazine and 3-aminopyridazine were also suitable in this cascade.
Ligand-Controlled Regioselective Copper-Catalyzed Trifluoromethylation To Generate (Trifluoromethyl)allenes
Ambler, Brett R.,Peddi, Santosh,Altman, Ryan A.
supporting information, p. 2506 - 2509 (2015/05/27)
(Chemical Equation Presented) "Cu-CF3" species have been used historically for a broad spectrum of nucleophilic trifluoromethylation reactions. Although recent advancements have employed ligands to stabilize and harness the reactivity of this key organometallic intermediate, the ability of a ligand to differentiate a regiochemical outcome of a Cu-CF3-mediated or -catalyzed reaction has not been previously reported. Herein, we report the first example of a Cu-catalyzed trifluoromethylation reaction in which a ligand controls the regiochemical outcome. More specifically, we demonstrate the ability of bipyridyl-derived ligands to control the regioselectivity of the Cu-catalyzed nucleophilic trifluoromethylation reactions of propargyl electrophiles to generate (trifluoromethyl)allenes. This method provides a variety of di-, tri-, and tetrasubstituted (trifluoromethyl)allenes, which can be further modified to generate complex fluorinated substructures.
Gold(I)-catalyzed decarboxylation of propargyl carbonates: Reactivity reversal of the gold catalyst from π-Lewis acidity to σ-Lewis acidity
Shen, Ruwei,Yang, Jianjun,Zhu, Shugao,Chen, Chao,Wu, Luling
supporting information, p. 1259 - 1269 (2015/04/22)
A cationic gold(I)-catalyzed decarboxylative etherification of propargyl carbonates to selectively produce propargyl ethers is reported. In the reaction the gold(I) catalyst shows a distinct σ-Lewis acidity rather than the commonly observed π-Lewis acidity, and thus catalyzes the decarboxylation of a variety of propargyl carbonates to give the corresponding propargyl ethers with high selectivity. This reaction represents a rare example of the tunable reactivity of cationic gold(I) complexes between σ-Lewis acidity and π-Lewis acidity.
Stereoselective, Cascade Synthesis of trans-Enynones through Coupling-Isomerization Reaction
Chinta, Bhavani Shankar,Baire, Beeraiah
, p. 10208 - 10217 (2015/11/03)
A mild, cascade methodology based on the modified Cadiot-Chodkiewicz reaction was developed for the stereoselective synthesis of trans-enynones. By this methodology, structurally divergent trans-enynones, which are embedded with sensitive functional groups, were synthesized. Control experiments suggested that the CuCl alone does not have a role in the isomerization step, whereas the CuCl-piperidine complex (formed during the cross coupling) may have a rate enhancing effect. Furthermore, additional sets of control experiments favor the involvement of unimolecular [1,2]-H shift rather than a homobimolecular proton abstraction during the isomerization step.
Direct synthesis of pyrroles via 1,3-dipolar cycloaddition of azomethine ylides with ynones
Wang, Zheng,Shi, Ying,Luo, Xiaoyan,Han, De-Man,Deng, Wei-Ping
supporting information, p. 1742 - 1745 (2013/06/27)
A direct and facile synthesis of multi-substituted pyrroles via AgOAc-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with ynones is developed, providing the corresponding adducts in moderate to high yields (up to 89%).
Catalytic decarboxylation of 2-alkynoic acids
Kolarovic, Andrej,Faberova, Zuzana
experimental part, p. 7199 - 7202 (2009/12/09)
(Chemical Equation Presented) A very efficient protocol enabling catalytic decarboxylation of a wide range of 2-alkynoic acids is described. The reaction conditions and the scope of the process are examined. The method is further utilized in a model decar
