79756-90-4Relevant academic research and scientific papers
Silver Mediated Banert Cascade with Carbon Nucleophiles
Alexander, Juliana R.,Kevorkian, Paul V.,Topczewski, Joseph J.
supporting information, p. 3227 - 3230 (2021/05/05)
The Banert cascade of propargylic azides can be promoted by simple silver salts, and the triazafulvene intermediate can be intercepted by carbon nucleophiles. Various indoles (>25 examples, up to 92% yield) and electron-rich heterocycles were effective. T
Intercepting the Banert cascade with nucleophilic fluorine: Direct access to α-fluorinated: N H-1,2,3-triazoles
Alexander,Kevorkian,Topczewski
supporting information, p. 5024 - 5027 (2021/05/28)
The treatment of propargylic azides with silver(i) fluoride in acetonitrile was found to yield α-fluorinated NH-1,2,3-triazoles via the Banert cascade. The reaction was regioselective and the products result from an initial [3,3] rearrangement. The reacti
Regioselective Iron-Catalysed Cross-Coupling Reaction of Aryl Propargylic Bromides and Aryl Grignard Reagents
Manjón-Mata, Inés,Quirós, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
supporting information, p. 146 - 151 (2019/12/11)
An iron-catalysed Kumada-type cross-coupling reaction between aryl substituted propargylic bromides and arylmagnesium reagents has been developed. Propargylic coupling products were the main or only outcome, and propargyl/allene regioselectivity was shown to depend on the electronic nature of the substituents on the triple bond of the substrate and on the arylmagnesium halide. Best selectivities were observed when electron donating substituents were present in either reagent. The process is stereoespecific, occurs with configuration inversion and no carbon-based radicals seem to be involved in the mechanism. (Figure presented.).
Nickel-Catalyzed Asymmetric Friedel-Crafts Propargylation of 3-Substituted Indoles with Propargylic Carbonates Bearing an Internal Alkyne Group
Miyazaki, Yusuke,Zhou, Biao,Tsuji, Hiroaki,Kawatsura, Motoi
supporting information, p. 2049 - 2053 (2020/03/04)
The nickel-catalyzed highly enantioselective Friedel-Crafts propargylation of 3-substituted indoles with propargylic carbonates bearing an internal alkyne group was developed. A wide array of the propargylic carbonates as well as 3-substituted indoles can be applicable to the asymmetric nickel catalysis, providing the corresponding chiral C-3 propargylated indolenine derivatives bearing two vicinal chiral centers in up to 89% yield with up to >99% ee and 94:6 dr (24 examples).
Kinetic Resolution of Propargylic Ethers via [2,3]-Wittig Rearrangement to Synthesize Chiral α-Hydroxyallenes
Xu, Xi,Dong, Shunxi,Feng, Lili,Wang, Sijing,Liu, Xiaohua,Feng, Xiaoming
supporting information, p. 2692 - 2696 (2020/03/30)
An efficient kinetic resolution of propargyloxy dicarbonyl compounds via asymmetric [2,3]-Wittig rearrangement was achieved by using a chiral N,N′-dioxide/NiII complex catalyst. Various chiral α-allenyl alcohols were obtained in high enantioselectivities under mild conditions. The utility of this method was readily demonstrated in the asymmetric synthesis of the chiral 2,5-dihydrofuran derivative.
Divergent Mechanisms of the Banert Cascade with Propargyl Azides
Alexander, Juliana R.,Packard, Mary H.,Hildebrandt, Alanna M.,Ott, Amy A.,Topczewski, Joseph J.
, p. 3174 - 3181 (2020/03/23)
Triazoles are privileged heterocycles for a variety of applications. The synthesis of 1H-triazoles can be accomplished by the Banert cascade from propargylic azides. Depending on the substrate and conditions, the Banert cascade can proceed by either a sigmatropic or prototropic mechanism. This report describes the first detailed kinetic analysis of the Banert cascade proceeding by both pathways including substituent effects and KIE. The analysis identified the inflection point in the divergent pathways, allowing future work to predict which Banert products are accessible.
Synthesis of substituted benzo[: B] [1,4]oxazepine derivatives by the reaction of 2-aminophenols with alkynones
Oshimoto, Kohei,Zhou, Biao,Tsuji, Hiroaki,Kawatsura, Motoi
supporting information, p. 415 - 419 (2020/01/30)
We have developed a novel synthetic method accessing benzo[b][1,4]oxazepines that are one of the rare classes of benzoxazepine derivatives by reaction of 2-aminophenols with alkynones in 1,4-dioxane at 100 °C. A series of benzo[b][1,4]oxazepine derivatives can be prepared by using this synthetic protocol. Mechanistic experiments indicated that the hydroxy proton of the aminophenol could play a crucial role in the formation of an alkynylketimine intermediate that undergoes 7-endo-dig cyclization.
Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: Synthesis of propargyl alcohols and α-ketoesters
Ni, Ke,Meng, Ling-Guo,Ruan, Hongjie,Wang, Lei
supporting information, p. 8438 - 8441 (2019/07/22)
The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere (N2 or O2). A N2 atmosphere favours propargyl alcohols via a direct C-C coupling process, whereas an O2 atmosphere results in the generation of α-ketoesters through the oxidative CC/C-O coupling pathway.
Phosphine-Catalyzed Intermolecular Annulations of Fluorinated ortho-Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition
Zhang, Yanshun,Sun, Yaoliang,Wei, Yin,Shi, Min
supporting information, p. 2129 - 2135 (2019/03/13)
A phosphine-catalyzed intermolecular annulation reaction of functionalized ortho-aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2-alkynylquinolines and benzo-fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. (Figure presented.).
Nickel-Catalyzed Asymmetric Propargylic Amination of Propargylic Carbonates Bearing an Internal Alkyne Group
Watanabe, Kouichi,Miyazaki, Yusuke,Okubo, Masataka,Zhou, Biao,Tsuji, Hiroaki,Kawatsura, Motoi
supporting information, p. 5448 - 5451 (2018/09/13)
We have achieved the nickel-catalyzed asymmetric propargylic amination of propargylic carbonates bearing an internal alkyne group. A wide variety of propargylic carbonates and N-methylaniline derivatives were tolerated under the reaction conditions, providing the corresponding chiral propargylic amines in up to 97% yield with up to 97% ee.
