N–H Insertion reactions of rhodium carbenoids. Part 5: A convenient route to 1,3-azoles
摘要:
Dirhodium(II) carboxylate catalysed reaction of diazocarbonyl compounds 2 in the presence of primary amides 1 results in the formation of alpha-acylaminoketones 3 (12 examples) by N-H insertion reaction of the intermediate rhodium carbene. The 1,4-dicarbonyl compounds 3 are readily converted into structurally diverse oxazoles 4 (11 examples) by cyclodehydration, thiazoles 5 (10 examples) by treatment with Lawesson's reagent, or imidazoles 6 (2 examples) by reaction with ammonia or methylamine. (C) 2004 Elsevier Ltd. All rights reserved.
Rh(III)-Catalyzed Regio- and Chemoselective [4 + 1]-Annulation of Azoxy Compounds with Diazoesters for the Synthesis of 2<i>H</i>-Indazoles: Roles of the Azoxy Oxygen Atom
作者:Zhen Long、Zhigang Wang、Danni Zhou、Danyang Wan、Jingsong You
DOI:10.1021/acs.orglett.7b00631
日期:2017.6.2
tandem C–H alkylation/intramolecular decarboxylative cyclization of azoxy compounds with diazoesters for the synthesis of 3-acyl-2H-indazoles is disclosed. The azoxy instead of the azo group enables a distinct approach for cyclative capture, leading to a [4 + 1]-annulation rather than a classic [4 + 2] manner. The azoxy oxygen atom is traceless after annulation, and further removal from the product is
Convergent Synthesis of Dihydropyrans from Catalytic Three-Component Reactions of Vinylcyclopropanes, Diazoesters, and Diphenyl Sulfoxide
作者:Ya-Lin Zhang、Rui-Ting Guo、Heng Luo、Xin-Shen Liang、Xiao-Chen Wang
DOI:10.1021/acs.orglett.0c01992
日期:2020.7.17
three-component reaction of vinylcyclopropanes, diazoesters, and diphenyl sulfoxide has been developed. The reaction gives polysubstituted dihydropyrans as the reactionproducts. Mechanistic studies indicate that isomerization of vinylcyclopropanes gives conjugated dienes, which then undergo [4 + 2]-cycloaddition with vicinaltricarbonyl compounds generated by oxygen atom transfer from diphenyl sulfoxide
Stereoselective synthesis of 4-substituted-cyclic sulfamidate-5-carboxylates by asymmetric transfer hydrogenation accompanied by dynamic kinetic resolution and applications to concise stereoselective syntheses of (−)-epi-cytoxazone and the taxotere side-chain
作者:Jin-ah Kim、Yeon Ji Seo、Soyeong Kang、Juae Han、Hyeon-Kyu Lee
DOI:10.1039/c4cc06395c
日期:——
DKR driven, asymmetric transfer hydrogenations of cyclic sulfamidate imine-5-carboxylates were developed.
DKR驱动的不对称转移氢化反应已经成功开发,用于环状磺胺酸酯亚胺-5-羧酸酯。
Zn(OAc)<sub>2</sub>-catalyzed tandem cyclization of isocyanides, α-diazoketones, and anhydrides: a general route to polysubstituted maleimides
A novel Zn(OAc)2-catalyzed three-component tandem cyclization reaction of isocyanides, α-diazoketones and anhydrides has been developed. The reaction demonstrates the wide scope of substrates and provides a novel and efficient strategy for the synthesis of polysubstituted maleimides from readily available substrates in a single step.
α-Alkylidene-γ-butyrolactone Formation via Bi(OTf)<sub>3</sub>-Catalyzed, Dehydrative, Ring-Opening Cyclizations of Cyclopropyl Carbinols: Understanding Substituent Effects and Predicting <i>E</i>/<i>Z</i> Selectivity
作者:Matthew J. Sandridge、Brett D. McLarney、Corey W. Williams、Stefan France
DOI:10.1021/acs.joc.7b01706
日期:2017.10.20
A Bi(OTf)3-catalyzed ring-opening cyclization of (hetero)aryl cyclopropyl carbinols to form α-alkylidene-γ-butyrolactones (ABLs) is reported. This transformation represents different chemoselectivity from previous reports that demonstrated formation of (hetero)aryl-fused cyclohexa-1,3-dienes upon acid-promoted cyclopropyl carbinol ring opening. ABLs are obtained in up to 89% yield with a general preference