Synthesis of ethers by GaBr3 -catalyzed reduction of carboxylic acid esters and lactones by siloxanes.

Ethers were synthesized by reduction of the respective esters catalyzed by gallium bromide (GaBr3 ) and using siloxanes, preferentially 1,1,3,3-tetramethyldisiloxane, as reductant. Methyl oleate, triglycerides, that is, tributyrine and glyceryl triundec-10-enoate as well as γ- and δ-lactones were converted into the respective ethers in high to moderate yields. γ-Lactones were reduced with high selectivity in the presence of a methyl ester functionality. The reduction has been carried out at room temperature or moderately elevated temperature of up to 60 °C using stoichiometric amounts of the reductant and 0.005-0.01 equiv of GaBr3 as catalyst per ester functionality without any solvent added. After a reaction time of 1-4 h the conversion of the substrate was 100 %. The product was separated from polymeric siloxanes formed as coupled product by simple distillation.

[1]  Martin Oestreich,et al.  Si-H-Bindungsaktivierung: Parallelen der Lewis-Säure-Katalyse mit Brookharts Iridium(III)-Pincerkomplex und B(C6F5)3† , 2013 .

[2]  T. Robert,et al.  Si-H bond activation: bridging Lewis acid catalysis with Brookhart's iridium(III) pincer complex and B(C6F5)3. , 2013, Angewandte Chemie.

[3]  M. Lemaire,et al.  Selective synthesis of 1-O-alkyl(poly)glycerol ethers by catalytic reductive alkylation of carboxylic acids with a recyclable catalytic system. , 2012, ChemSusChem.

[4]  M. Beller,et al.  Synthesis of ethers from esters via Fe-catalyzed hydrosilylation. , 2012, Chemical communications.

[5]  R. Hughes,et al.  Gallium(III)-catalyzed three-component (4+3) cycloaddition reactions. , 2012, Angewandte Chemie.

[6]  M. Yasuda,et al.  Gallium tribromide catalyzed coupling reaction of alkenyl ethers with ketene silyl acetals. , 2012, Angewandte Chemie.

[7]  Jia Deng.  1,1,3,3-Tetramethyldisiloxane , 2011 .

[8]  Hans J. Schäfer,et al.  Fette und Öle als nachwachsende Rohstoffe in der Chemie , 2011 .

[9]  Uwe Bornscheuer,et al.  Oils and fats as renewable raw materials in chemistry. , 2011, Angewandte Chemie.

[10]  M. Meier,et al.  Cross-metathesis of unsaturated triglycerides with methyl acrylate: Synthesis of a dimeric metathesis product , 2011 .

[11]  Hui-jing Li,et al.  A gallium-catalyzed cycloisomerization/Friedel-Crafts tandem. , 2010, The Journal of organic chemistry.

[12]  J. Čejka,et al.  Zeolites efficiently promote the cyclization of nonactivated unsaturated alcohols. , 2010, Chemistry.

[13]  Pascual Pérez,et al.  Green solvents from glycerol. Synthesis and physico-chemical properties of alkyl glycerol ethers , 2010 .

[14]  T. Konakahara,et al.  Direct Reduction of Esters toEthers with an Indium(III) Bromide/TriethylsilaneCatalytic System , 2008 .

[15]  T. Konakahara,et al.  A Green Reagent for the Iodinationof Phenols , 2008 .

[16]  T. Konakahara,et al.  An efficient one-pot synthesis of unsymmetrical ethers: a directly reductive deoxygenation of esters using an InBr3/Et3SiH catalytic system. , 2007, The Journal of organic chemistry.

[17]  E. Duñach,et al.  Triflic acid-catalysed cyclisation of unsaturated alcohols , 2004 .

[18]  Hans J. Schäfer,et al.  Neue Synthesen mit Ölen und Fetten als nachwachsende Rohstoffe für die chemische Industrie , 2000 .

[19]  W. Friedt,et al.  New Syntheses with Oils and Fats as Renewable Raw Materials for the Chemical Industry. , 2000, Angewandte Chemie.

[20]  J. Metzger.  Solvent-Free Organic Syntheses. , 1998, Angewandte Chemie.

[21]  J. Metzger.  Lösungsmittelfreie organische Synthesen , 1998 .

[22]  S. Buchwald,et al.  CONVENIENT TWO-STEP CONVERSION OF LACTONES INTO CYCLIC ETHERS , 1998 .

[23]  J. Metzger,et al.  Radical Additions of Alkyl 2‐Haloalkanoates and 2‐Haloalkanenitriles to Alkenes Initiated by Electron Transfer from Copper in Solvent‐Free Systems , 1997 .

[24]  M. Berger,et al.  Carba analogues of triglycerides--isosteric mimics for natural lipids. Novel substrates for the determination of regio- and enantioselectivities displayed by lipases. , 1994, Bioorganic & medicinal chemistry.

[25]  A. Katritzky,et al.  Addition of benzotriazole to vinyl ethers. Chemistry of the adducts , 1990 .

[26]  H. K. Mangold.  Synthese und Biosynthese von Alkoxylipiden , 1979 .

[27]  H. Mangold.  Synthesis and biosynthesis of alkoxylipids. , 1979, Angewandte Chemie.

[28]  V. Müller.  Synthese und Eigenschaften gesättigter Trialkylglycerinäther , 1977 .

[29]  A. Branen,et al.  Synthesis of long chain alkyl glyceryl ethers from triglycerides using boron trifluoride etherate and lithium aluminum hydride , 1975 .

[30]  H. Mangold,et al.  Reactions of Aliphatic Methanesulfonates. II. Syntheses of Long-Chain Di- and Trialkyl Glyceryl Ethers1 , 1966 .

[31]  H. Mangold,et al.  Reactions of Aliphatic Methanesulfonates. I. Syntheses of Long-Chain Glyceryl-(1) Ethers1 , 1964 .

[32]  H. Brown,et al.  Kinetics and Relative Rates of the Gallium Bromide-Catalyzed Reactions of Alkyl Bromides with Aromatic Hydrocarbons in 1,2,4-Trichlorobenzene Solution , 1963 .