- Facile One-Pot Transformation of Primary Alcohols into 3-Aryl- and 3-Alkyl-isoxazoles and -pyrazoles
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Various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylisoxazoles in good yields in one pot by successive treatment with PhI(OAc) 2 in the presence of TEMPO, NH 2 OH, and then NCS, followed by reaction with alkynes in the presence of Et 3 N. Similarly, various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylpyrazoles in good yields in one pot by successive treatment with PhI(OAc) 2 in the presence of TEMPO, PhNHNH 2, and then NCS and decyl methyl sulfide, followed by reaction with alkynes in the presence of Et 3 N. Thus, both 3-aryl- and 3-alkylisoxazoles, and 3-aryl- and 3-alkylpyrazoles could be prepared from readily available primary alcohols in one pot under transition-metal-free conditions.
- Kobayashi, Eiji,Togo, Hideo
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p. 3723 - 3735
(2019/09/30)
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- Stereospecific copper(II)-catalyzed tandem ring opening/oxidative alkylation of donor-acceptor cyclopropanes with hydrazones: Synthesis of tetrahydropyridazines
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Aerobic copper(II)-catalyzed tandem ring opening and oxidative C-H alkylation of donor-acceptor cyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89-98% enantiomeric excess). The substrate scope, functional group tolerance, dual role of the copper(II) catalyst, and the use of air as an oxidant are the important practical features. A product bearing a 3-bromoaryl group can be subjected to Pd-catalyzed Suzuki coupling with boronic acid in high yield.
- Mishra, Manmath,De, Pinaki Bhusan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
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p. 10901 - 10910
(2019/09/13)
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- Synthesis of tetrahydropyridazines by a metal-carbene-directed enantioselective vinylogous N-H insertion/Lewis acid-catalyzed diastereoselective Mannich addition
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A versatile cascade of reactions, triggered by RhII-catalyzed diazo decomposition followed by a vinylogous N-H insertion/Lewis acid catalyzed Mannich addition, that produces highly substituted 1,2,3,6-tetrahydropyridazines in up to 97% ee with high yield and diastereocontrol has been developed. Copyright
- Xu, Xinfang,Zavalij, Peter Y.,Doyle, Michael P.
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supporting information
p. 9829 - 9833
(2012/11/07)
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