29978-38-9Relevant 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
supporting information, 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.
Enantioselective [3 + 2] annulation of 4-isothiocyanato pyrazolones and alkynyl ketones under organocatalysis
Wang, Wenyao,Wei, Shiqiang,Bao, Xiaoze,Nawaz, Shah,Qu, Jingping,Wang, Baomin
, p. 1145 - 1154 (2021/02/16)
An asymmetric [3 + 2] annulation reaction of 4-isothiocyanato pyrazolones with alkynyl ketones in the presence of an organic catalyst derived from a cinchona alkaloid under mild conditions is realized. This protocol provides unprecedented expeditious access to a wide range of optically active spiro[pyrroline-pyrazolones] with various electronic properties in high yields with good to excellent enantioselectivities.
Regioselectivity Switch in Palladium-Catalyzed Allenylic Cycloadditions of Allenic Esters: [4+1] or [4+3] Cycloaddition/Cross-Coupling
Li, Long,Luo, Pengfei,Deng, Yuhua,Shao, Zhihui
supporting information, p. 4710 - 4713 (2019/03/08)
The first Pd-catalyzed asymmetric allenylic [4+1] cycloaddition was successfully developed. Alternatively, tuning the Pd catalyst switched the reactivity toward an unprecedented [4+3] cycloaddition/cross-coupling. Ligands play a vital role in controlling the reaction pathway, allowing highly selective access to different products from identical substrates. Biological evaluation of the obtained compounds led to the discovery of new antitumor targets. A possible mechanism is proposed, suggesting two interesting catalytic cycles for the cycloaddition with palladium-butadienyls. This study also demonstrated the potential and utility of allenic esters as 1,4-biselectrophiles and C4 synthons for participating in cycloaddition reactions.
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.
Copper- and borinic acid-catalyzed propargylic etherification of propargylic carbonates with benzyl alcohols
Tsuchida, Kohei,Yuki, Masahiro,Nakajima, Kazunari,Nishibayashi, Yoshiaki
supporting information, p. 671 - 673 (2018/04/30)
Propargylic substitution reactions have offered useful synthetic methods because further transformations based onthe alkyne moiety in the propargylic substituted products are readily achieved to construct more complex organic compounds. A large number of studies have been devoted to enantioselective propargylic substitution reactions with a variety of nucleophiles. However, successful examples of the use of alcohols as nucleophiles have been quite limited until now. To achieve utilization of aliphatic alcohols, herein we report the use of combined catalysis of a copper-pybox complex and a borinic acid. In this catalytic system, aliphatic alcohols such as benzyl alcohol derivatives were successfully applied to afford the corresponding propargylic etherified products in good yields with high enantioselectivities.
Cooperative catalysis: Enantioselective propargylic alkylation of propargylic alcohols with enecarbamates using ruthenium/Phosphoramide hybrid catalysts
Senda, Yasushi,Nakajima, Kazunari,Nishibayashi, Yoshiaki
supporting information, p. 4060 - 4064 (2015/03/30)
The diastereo- and enantioselective propargylic alkylation of propargylic alcohols with E-enecarbamates in the presence of a catalytic amount of thiolate-bridged diruthenium complexes bearing an optically active phosphoramide moiety gives the corresponding propargylic alkylated products (up to 97 % ee).
Bronsted acid mediated nitrogenation of propargylic alcohols: An efficient approach to alkenyl nitriles
Huang, Xiaoqiang,Jiao, Ning
supporting information, p. 4324 - 4328 (2014/06/23)
A novel and efficient approach to alkenyl nitriles from readily available propargylic alcohols has been developed. This nitrogenation reaction is transition-metal-free and could be conducted under air at ambient temperature, which makes this protocol promising and practical. Moreover, NH4Br is disclosed as an efficient additive to promote the stereoselectivity of this reaction. the Partner Organisations 2014.
Palladacycle-catalyzed reaction of bicyclic alkenes with terminal ynones: Regiospecific synthesis of polysubstituted furans
Ge, Guang-Cun,Mo, Dong-Liang,Ding, Chang-Hua,Dai, Li-Xin,Hou, Xue-Long
, p. 5756 - 5759 (2013/01/15)
A new synthetic strategy to access polysubstituted furans regiospecifically has been developed using simple bicyclic alkenes and terminal ynones as starting materials with palladacycles as unique active catalysts. A rational mechanism has also been proposed. This reaction features mild reaction conditions, easily available starting materials and palladacycle catalysts, a wide substrate scope, and high regiospecificity.
Chiral silver phosphate-catalyzed cycloisomeric kinetic resolution of α-allenic alcohols
Wang, Yan,Zheng, Kuan,Hong, Ran
supporting information; scheme or table, p. 4096 - 4099 (2012/04/10)
A kinetic resolution of α-allenic alcohols is realized through chiral silver phosphate-catalyzed cycloisomerization with high stereoselectivity (selectivity factor up to 189) and tolerance of a variety of functional groups. A mechanistic model is proposed to interpret the origin of the high stereoselectivity and broad substrate scope.
Base-catalyzed cascade 1,3-H shift/cyclization reaction to construct polyaromatic furans
Wang, Ya-Hui,Liu, Heng,Zhu, Li-Li,Li, Xiao-Xiao,Chen, Zili
, p. 707 - 712 (2011/05/06)
A convenient new method was developed to prepare unfused polyaromatic furan derivatives from diynyl-1,6-diols through a novel base-catalyzed cascade 1,3-H shift/cyclization process. Deuterium experiments were performed to determine that the 1,3-H shift was the rate-determining step. Copyright
