The hydrodeoxygenation of bioderived furans into alkanes.

The conversion of biomass into fuels and chemical feedstocks is one part of a drive to reduce the world's dependence on crude oil. For transportation fuels in particular, wholesale replacement of a fuel is logistically problematic, not least because of the infrastructure that is already in place. Here, we describe the catalytic defunctionalization of a series of biomass-derived molecules to provide linear alkanes suitable for use as transportation fuels.

Acid-, water- and high-temperature-stable ruthenium complexes for the total catalytic deoxygenation of glycerol to propane.

The ruthenium aqua complexes [Ru(H(2)O)(2)(bipy)(2)](OTf)(2), [cis-Ru(6,6'-Cl(2)-bipy)(2)(OH(2))(2)](OTf)(2), [Ru(H(2)O)(2)(phen)(2)](OTf)(2), [Ru(H(2)O)(3)(2,2':6',2''-terpy)](OTf)(2) and [Ru(H(2)O)(3)(Phterpy)](OTf)(2) (bipy = 2,2'-bipyridine; OTf(-) = triflate; phen = phenanthroline; terpy = terpyridine; Phterpy = 4'-phenyl-2,2':6',2''-terpyridine) are water- and acid-stable catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOS(O)(2)CF(3) (triflic acid) as a dehydration co-catalyst they directly convert 1,2-hexanediol to n-hexanol and hexane. The terpyridine complexes are stable and active as catalysts at temperatures > or = 250 degrees C and in either aqueous sulfolane solution or pure water convert glycerol into n-propanol and ultimately propane as the final reaction product in up to quantitative yield.

Selective deoxygenation of sugar polyols to alpha,omega-diols and other oxygen content reduced materials--a new challenge to homogeneous ionic hydrogenation and hydrogenolysis catalysis.

An oxygen atom on every carbon--this is the problem! While nature provides linear C(3) to C(6) building blocks in the form of sugar alcohols in large and renewable abundance, they are overfunctionalized for the purpose of most chemical applications. Selective deoxygenation by anthropogenic catalyst systems may be one answer to this challenge.

Regioselectively trisilylated hexopyranosides through homogeneously catalyzed silane alcoholysis.

The iridium complex [Ir(COD)(PPh3)2]+ SbF6- reacts with tert-butyldimethylsilane in DMA to form [IrH2(Sol)2(PPh3)2]+ SbF6-, which is an active catalyst for the regioselective di- and trisilylation of a series of representative methyl hexopyranosides, beta-1,6-anhydrohexopyranosides and 1,3,5-O-methylidene inositol. The corresponding 2,3,6- and 2,4,6-silylated glycosides are obtained in a separable mixture of 47-89% (2,3,6-isomers) and 9-25% (2,4,6-isomers) yield in a single-pot reaction. The 2,4-disilylated derivatives of mannosan, galactosan, and 1,3,5-O-methylidene inositol as well as persilylated levoglucosan are accessible in >85% yield by this method.

A catalytic synthesis of thiosilanes and silthianes: palladium nanoparticle-mediated cross-coupling of silanes with thio phenyl and thio vinyl ethers through selective carbon-sulfur bond activation.

Palladium nanoparticles generated in situ from N,N-dimethyl-acetamide (DMA) solutions of PdX(2) (X = Cl(-), OAc(-), OCOCF(3)(-)) or Pd(2)(dba)(3) by reduction with alkyl silanes R(3)SiH (R = Me, Et, i-Pr, t-Bu) are selective catalysts for the cross-coupling of the silanes R(3)SiH with phenyl and vinyl thioethers forming the corresponding thiosilanes and silthianes in high yields and under mild conditions. The method is applicable to phenyl thioglycosides, giving access to thiosilyl glycosides a new class of sugar derivatives.

Synthesis of allyl and alkyl vinyl ethers using an in situ prepared air-stable palladium catalyst. Efficient transfer vinylation of primary, secondary, and tertiary alcohols.

An air-stable palladium catalyst formed in situ from commercially available components efficiently catalyzed the transfer vinylation between butyl vinyl ether and various allyl and alkyl alcohols to give the corresponding allyl and alkyl vinyl ethers in 61-98% yield in a single step.

Regioselective silylation of sugars through palladium nanoparticle-catalyzed silane alcoholysis.

Palladium(0)-catalyzed silane alcoholysis was applied to sugars for the first time using tert-butyldimethylsilane (TBDMS-H) and Ph(3)SiH as the silanes. The catalyst is a colloidal solution of Pd(0) generated in situ from PdX(2) (X = Cl(-), OAc(-)) and TBDMS-H in N,N-dimethylacetamide. The colloid has been characterized by dynamic light scattering and transmission electron microscopy and consists of catalytically highly active nanoparticles of approximately 2 nm diameter.

Palladium(II)-catalyzed transfer vinylation of protected monosaccharides.

A method for the catalytic vinylation of protected monosaccharides bearing a single free hydroxyl function has been developed. Reaction of representative primary, secondary, and anomeric sugar hydroxyl functions with butyl vinyl ether as the reactant and solvent and (phen)Pd(OAc)(2) (phen = 1,10-phenanthroline ligand) as the catalyst gives the corresponding vinylated sugar products in 36-79% yield. The catalyst requires the presence of traces of oxygen in the reaction mixture to prevent decomposition to Pd(0).

Metal-Catalyzed Selective Deoxygenation of Diols to Alcohols.

The internal OH group of 1,2-propanediol is selectively removed in the deoxygenation catalyzed by [{Cp*Ru(CO) } (μ-H)] OTf (1, Cp*=C Me , OTf=trifluoromethanesulfonate; see scheme). This reaction provides a model for deoxygenation of polyols derived from carbohydrates, for use in alternative, biomass-based feedstock applications. An ionic mechanism is proposed that involves the dihydrogen complex [Cp*Ru(CO) (η -H )] .