4131-50-4Relevant academic research and scientific papers
Facile Conversion of Molecularly Complex (Hetero)aryl Carboxylic Acids into Alkynes for Accelerated SAR Exploration
Lutter, Ferdinand H.,Jouffroy, Matthieu
supporting information, p. 14816 - 14820 (2021/10/08)
1,2,3-Triazoles are well-established bioisosteres for amides, often installed as a result of structure?activity-relationship (SAR) exploration. A straightforward approach to assess the effect of the replacement of an amide by a triazole would start from the carboxylic acid and the amine used for the formation of a given amide and convert them into the corresponding alkyne and azide for cyclization by copper-catalyzed alkyne?azide cycloaddition (CuAAC). Herein, we report a functional-group-tolerant and operationally simple decarbonylative alkynylation that allows the conversion of complex (hetero)aryl carboxylic acids into alkynes. Furthermore, the utility of this method was demonstrated in the preparation of a triazolo analog of the commercial drug moclobemide. Lastly, mechanistic investigations using labeled carboxylic acid derivatives clearly show the decarbonylative nature of this transformation.
Decarbonylative Sonogashira Cross-Coupling of Carboxylic Acids
Liu, Chengwei,Szostak, Michal
supporting information, p. 4726 - 4730 (2021/06/28)
Decarbonylative Sonogashira cross-coupling of carboxylic acids by palladium catalysis is presented. The carboxylic acid is activated in situ by the formation of a mixed anhydride and further decarbonylates using the Pd(OAc)2/Xantphos system to provide an aryl-Pd intermediate, which is intercepted by alkynes to access the traditional Pd(0)/(II) cycle using carboxylic acids as ubiquitous and orthogonal electrophilic cross-coupling partners. The methodology efficiently constructs new C(sp2)-C(sp) bonds and can be applied to the derivatization of pharmaceuticals. Mechanistic studies give support to decarbonylation preceding transmetalation in this process.
Nickel-Catalyzed Decarbonylative Alkynylation of Acyl Fluorides with Terminal Alkynes under Copper-Free Conditions
Chen, Qiang,Fu, Liyan,You, Jingwen,Nishihara, Yasushi
supporting information, p. 1560 - 1564 (2020/11/12)
Nickel-catalyzed decarbonylative alkynylation of acyl fluorides with terminal silylethynes under copper-free conditions is described. This newly developed method has a wide substrate scope, affording internal silylethynes in moderate to high yields. The formation of 1,3-diynes as homocoupled products and conjugate enones as carbonyl-retentive products were effectively suppressed.
Catalytic Decarboxylation of Silyl Alkynoates to Alkynylsilanes
Aoyagi, Keiya,Choi, Jun-Chul,Kawatsu, Takahiro,Matsumoto, Kazuhiro,Nakajima, Yumiko,Sato, Kazuhiko
, (2020/09/15)
Herein, we describe a decarboxylative approach to the preparation of alkynylsilanes. Treatment of a silyl alkynoate in N,N-dimethylformamide (DMF) at 80 °C in the presence of catalytic amounts of CuCl and PCy3 produced the corresponding alkynylsilane in excellent yield. The copper-catalyzed decarboxylation proceeded smoothly with low catalyst loadings (0.5 mol % of CuCl and 1.0 mol % of PCy3) under mild reaction conditions and is easily scalable to gram quantities.
Diborative Reduction of Alkynes to 1,2-Diboryl-1,2-Dimetalloalkanes: Its Application for the Synthesis of Diverse 1,2-Bis(boronate)s
Takahashi, Fumiya,Nogi, Keisuke,Sasamori, Takahiro,Yorimitsu, Hideki
supporting information, p. 4739 - 4744 (2019/06/27)
Reduction of alkynes with alkali metals in the presence of B2pin2 results in diboration of alkynes. Distinct from conventional dissolving metal hydrogenations, two carbon-boron bonds and also two carbon-alkali metal bonds can be constructed in one operation to form 1,2-diboryl-1,2-dimetalloalkanes. The 1,2-diboryl-1,2-dimetalloalkanes generated are readily convertible to a wide range of vicinal bis(boronate)s. In particular, oxidation of the 1,2-dianionic species provides (E)-1,2-diborylalkenes, unique anti-selective diboration of alkynes being thus executed.
Sterically Controlled Late-Stage C-H Alkynylation of Arenes
Mondal, Arup,Chen, Hao,Fl?mig, Lea,Wedi, Philipp,Van Gemmeren, Manuel
supporting information, p. 18662 - 18667 (2019/11/28)
Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials, and reagents. These molecules are typically prepared from prefunctionalized starting materials, e.g. using the Sonogashira coupling, or using directing group-based C-H activation strategies. While highly efficient, these approaches remain limited by their inherent selectivities for specific regioisomers. Herein we present a complementary approach based on an arene-limited nondirected C-H activation. The reaction is predominantly controlled by steric rather than electronic factors and thereby gives access to a complementary product spectrum with respect to traditional methods. A broad scope as well as the suitability of this protocol for late-stage functionalization are demonstrated.
Nickel-Catalyzed Decarboxylative C–Si Bond Formation: A Regioselective Cross-Coupling Between Trialkyl Silanes and α,β-Unsaturated Carboxylic Acids
Allam, Bharat Kumar,Azeez, Sadaf,Kandasamy, Jeyakumar
, (2019/08/26)
This report presents the first example of nickel-catalyzed mild decarboxylative cross-coupling reaction for the regioselective formation of C–Si bond. An easily accessible and significantly stable Ni (dmg)2 owes the role of key promoter. This r
Geometric E→Z Isomerisation of Alkenyl Silanes by Selective Energy Transfer Catalysis: Stereodivergent Synthesis of Triarylethylenes via a Formal anti-Metallometallation
Fa?bender, Svenja I.,Molloy, John J.,Mück-Lichtenfeld, Christian,Gilmour, Ryan
supporting information, p. 18619 - 18626 (2019/11/16)
An efficient geometrical E→Z isomerisation of alkenyl silanes is disclosed via selective energy transfer using an inexpensive organic sensitiser. Characterised by operational simplicity, short reaction times (2 h), and broad substrate tolerance, the reaction displays high selectivity for trisubstituted systems (Z/E up to 95:5). In contrast to thermal activation, directionality results from deconjugation of the π-system in the Z-isomer due to A1,3-strain thereby inhibiting re-activation. The structural importance of the β-substituent logically prompted an investigation of mixed bis-nucleophiles (Si, Sn, B). These versatile linchpins also undergo facile isomerisation, thereby enabling a formal anti-metallometallation. Mechanistic interrogation, supported by a theoretical investigation, is disclosed together with application of the products to the stereospecific synthesis of biologically relevant target structures.
Et2Zn-mediated stoichiometric C(sp)-H silylation of 1-alkynes and chlorosilanes
Huang, Pan,Xu, Dawen,Reich, Robert M.,Kaiser, Felix,Liu, Boping,Kühn, Fritz E.
supporting information, p. 1574 - 1577 (2019/05/17)
A first example of an Et2Zn mediated silylation of 1-aklynes is reported. A series of functional groups are tolerated in this reaction. Mechanistic studies support Zn alkynilides as intermediates in the reaction. This reaction protocol provides a practical method for the preparation of alkynylsilanes and expands the application of organometallic zinc in organic synthesis.
Chemoselective Aerobic Cross-Dehydrogenative Coupling of Terminal Alkynes with Hydrosilanes by a Nanoporous Gold Catalyst
Kavthe, Rahul D.,Ishikawa, Yoshifumi,Kusuma, Indra,Asao, Naoki
supporting information, p. 15777 - 15780 (2018/10/09)
Aerobic cross-dehydrogenative coupling between terminal alkynes and hydrosilanes occurred in the presence of nanoporous gold catalyst under O2 atmosphere. A variety of alkynylsilanes were synthesized in good-to-high yields and the catalyst was easily recovered and reused many times. Furthermore, the chemoselective direct silyl protection of terminal acetylenes of alkynols over the hydroxyl groups was achieved with this catalytic system.
