78330-53-7Relevant academic research and scientific papers
Highly Efficient, Convergent, and Enantioselective Synthesis of Phthioceranic Acid
Xu, Shiqing,Oda, Akimichi,Bobinski, Thomas,Li, Haijun,Matsueda, Yohei,Negishi, Ei-Ichi
, p. 9319 - 9322 (2015)
A new strategy for highly concise, convergent, and enantioselective access to polydeoxypropionates has been developed. ZACA-Pd-catalyzed vinylation was used to prepare smaller deoxypropionate fragments, and then two key sequential Cu-catalyzed stereocontrolled sp3-sp3 cross-coupling reactions allowed convergent assembly of smaller building blocks to build-up long polydeoxypropionate chains with excellent stereoselectivity. We employed this strategy for the synthesis of phthioceranic acid, a key constituent of the cell-wall lipid of Mycobacterium tuberculosis, in just 8 longest linear steps with full stereocontrol. A step-economical synthesis of phthioceranic acid was achieved by using a conceptually new strategy. ZACA-Pd-catalyzed vinylation was used to prepare smaller deoxypropionate building blocks. Then two Cu-catalyzed stereospecific sp3-sp3 cross-couplings linked the smaller fragments together with full inversion of configuration to assemble large polydeoxypropionates in a stereoselective manner. ZACA=Zr-catalyzed asymmetric carboalumination of alkenes.
In Situ Generated Gold Nanoparticles on Active Carbon as Reusable Highly Efficient Catalysts for a Csp3 ?Csp3 Stille Coupling
Holz, Julia,Pfeffer, Camilla,Zuo, Hualiang,Beierlein, Dennis,Richter, Gunther,Klemm, Elias,Peters, René
, p. 10330 - 10334 (2019/06/27)
Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional Csp2-Csp2 cross-coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form Csp3-Csp3 bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross-coupling reaction of an organic halide and an organometallic reagent.
One-Step Homologation for the Catalytic Asymmetric Synthesis of Deoxypropionates
Xu, Shiqing,Li, Haijun,Komiyama, Masato,Oda, Akimichi,Negishi, Ei-Ichi
supporting information, p. 149 - 156 (2017/01/09)
A one-step homologation protocol for the synthesis of natural products containing deoxypropionate motif is described by the combination of Zr-catalyzed asymmetric carboalumination of alkenes (ZACA)-Pd-catalyzed vinylation and ZACA–oxidation reaction. In contrast to most other synthetic strategies used to date that typically require three steps per deoxypropionate unit due to the functional-group interconversions, our one-step homologation strategy promises to provide a general and more efficient synthetic route toward deoxypropionate natural products as exemplified by significant improvements in the syntheses of intermediates and/or final products of mycolipenic acid 1 and its analogue 2, (?)-rasfonin, and syn- and anti-dicarboxylic acids 5 and 6.
Protodeboronation of tertiary boronic esters: Asymmetric synthesis of tertiary alkyl stereogenic centers
Nave, Stefan,Sonawane, Ravindra P.,Elford, Tim G.,Aggarwal, Varinder K.
, p. 17096 - 17098 (2011/03/01)
While tertiary boranes undergo efficient protodeboronation with carboxylic acids, tertiary boronic esters do not. Instead, we have discovered that CsF with 1.1 equiv of H2O (on tertiary diarylalkyl boronic esters) or TBAF?3H2O (on tertiary aryldialkyl boronic esters) effect highly efficient protodeboronation of tertiary boronic esters with essentially complete retention of configuration. Furthermore, substituting D2O for H2O provides ready access to deuterium-labeled enantioenriched tertiary alkanes. The methodology has been applied to a short synthesis of the sesquiterpene, (S)-turmerone.
All-catalytic, efficient, and asymmetric synthesis of α,ω- diheterofunctional reduced polypropionates via "one-pot" Zr-catalyzed asymmetric carboalumination - Pd-catalyzed cross-coupling tandem process
Novak, Tibor,Tan, Ze,Liang, Bo,Negishi, Ei-Ichi
, p. 2838 - 2839 (2007/10/03)
A highly efficient method for the synthesis of stereochemically pure (≥99% ee and >50/1 dr) α,ω-diheterofunctional reduced polypropionates has been developed. The essential features of the method are represented by the conversion of inexpensive styrene in
Titanium(IV)-Catalyzed Dynamic Kinetic Asymmetric Transformation of Alcohols, Silyl Ethers, and Acetals under Carbon Allylation
Braun, Manfred,Kotter, Wolfgang
, p. 514 - 517 (2007/10/03)
High yields and enantioselectivities are obtained in a dynamic kinetic asymmetric transformation in which the C-O bond of alcohols, silyl ethers, and acetals are substituted by a C-C bond. For example, the racemic indanyl silyl ether 1 is converted into (S)-2 in the presence of the chiral Lewis acidic TiIV complex 3.
Macrocyclic diphosphine ligands in asymmetric carbon-carbon bond-forming reactions
Widhalm, Michael,Wimmer, Petra,Klintschar, Gerd
, p. 167 - 178 (2007/10/03)
Seven chiral macrocyclic ligands with potential O2P2 and N2P2 coordination sites owing their chirality from the incorporation of an axial-chiral binaphthyl unit were used as chiral auxiliaries in transition meta
