29805-14-9Relevant academic research and scientific papers
Iridium-Catalyzed Enantioselective and Chemodivergent Allenylic Alkylation of Vinyl Azides for the Synthesis of α-Allenylic Amides and Ketones**
Chakrabarty, Aditya,Mukherjee, Santanu
supporting information, (2022/02/07)
The first enantioselective synthesis of α-allenylic amides and ketones through allenylic alkylation of vinyl azides is reported. In these chemodivergent reactions, cooperatively catalyzed by a IrI/(phosphoramidite,olefin) complex and Sc(OTf)3, vinyl azides act as the surrogate for both amide enolates and ketone enolates. The desiccant (molecular sieves) plays a crucial role in controlling the chemodivergency of this enantioconvergent and regioselective reaction: Under otherwise identical reaction conditions, the presence of the desiccant led to α-allenylic amides, while its absence resulted in α-allenylic ketones. Utilizing racemic allenylic alcohols as the alkylating agent, the overall process represents a dynamic kinetic asymmetric transformation (DyKAT), where both the products are formed with the same absolute configuration. To the best of our knowledge, this is the first example of the use of vinyl azide as the ketone enolate surrogate in an enantioselective transformation.
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.
Diversity-oriented synthesis based on the dppp-catalyzed mixed double-michael reactions of electron-deficient acetylenes and β-amino alcohols
Fan, Yi Chiao,Kwon, Ohyun
scheme or table, p. 3802 - 3825 (2011/06/24)
In this study, we prepared oxizolidines through 1,3-bis(diphenylphosphino)- propane (DPPP)-catalyzed mixed double-Michael reactions of β-amino alcohols with electron-deficient acetylenes. These reactions are very suitable for the diversity-oriented parallel syntheses of oxizolidines because: (i) they are performed under mild metal-free conditions and (ii) the products are isolated without complicated work-up. To demonstrate the applicability of mixed double-Michael reactions for the preparation of five-membered-ring heterocycles, we prepared 60 distinct oxazolidines from five β-amino alcohols and 12 electron-deficient acetylenes. We synthesized 36 of these 60 oxazolidines in enantiomerically pure form from proteinogenic amino acid-derived β-amino alcohols.
Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
supporting information; experimental part, p. 500 - 511 (2011/04/17)
A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph 3PAuCl and 1% AgSbF6 in dioxane-H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring carbonyl group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methyl ketone is transformed to 1,2-diol and 1,2-amino alcohol derivatives. Synthesis of actinopolymorphol B is achieved for the first time involving hydration of the propargyl acetate as the key step.
Nematicidal pyrazoles
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, (2008/06/13)
Novel pyrazoles of formula (1) wherein R1 represents halogen, C1-6 alkyl, C1-5 haloalkyl, C2-6 alkoxy, C1-4 alkylthio, C2-5 alkenyloxy, C3-5 alkynyloxy, C2-6 (total carbon number) alkoxyalkyl, C2-6 (total carbon number) alkylthioalkyl, C1-5 haloalkoxy, C2-6 (total carbon number) alkoxyalkoxy, hydroxy or optionally substituted phenyl, R2 represents hydrogen, halogen, C1-5 alkyl, C2-6 (total carbon number) alkoxyalkyl, C2-6 (total carbon number) alkylthioalkyl, C2-6 (total carbon number) alkylsulfinylalkyl, C2-6 (total carbon number alkylsulfonylalkyl or C1-5 haloalkyl, R3 represents hydrogen, C1-5 alkyl, —COR4, COOR5, CH(OR6)2 or CH2Si(R7)3, R4 represents C1-10 alkyl, C1-6 haloalkyl, C2-6 alkenyl, optionally substituted C3-6 cycloalkyl, C2-6 (total carbon number) alkoxyalkyl, C2-6 (total carbon number alkylthioalkyl, optionally substituted phenyl, C1-6 haloalkyl, alkylamino, di-(C1-6 alkyl)amino or optionally substituted phenylamino, R5 represents C1-7 alkyl, R6 and R7 represent C1-6 alkyl, and n is 1, 2 or 3, and when n is 2 or 3, the corresponding number (n) of R1 radicals may be the same or different, processes for preparing these compounds and their use as nematicides and anthelmintics.
