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Efficient reduction of the tertiary amide bond in amino acid derivatives and peptides is described. Functional group selectivity has been achieved by applying a commercially available rhodium precursor and bis(diphenylphosphino)propane (dppp) ligand together with phenyl silane as a reductant. This methodology allows for specific reductive derivatization of biologically interesting peptides and offers straightforward access to a variety of novel peptide derivatives for chemical biology studies and potential pharmaceutical applications. The catalytic system tolerates a variety of functional groups including secondary amides, ester, nitrile, thiomethyl, and hydroxy groups. This convenient hydrosilylation reaction proceeds at ambient conditions and is operationally safe because no air-sensitive reagents or highly reactive metal hydrides are needed. [ABSTRACT FROM AUTHOR]

The 'green' reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced. [ABSTRACT FROM AUTHOR]

Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. [ABSTRACT FROM AUTHOR]

Formation of C-C bonds from CO2 is a much sought after reaction in organic synthesis. To date, other than C-H carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about C-C bond formation. In fact, to the best of our knowledge no catalytic methylation of C-H bonds using CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient methylation of carbon nucleophiles such as indoles, pyrroles, and electron-rich arenes. Comparison experiments which employ paraformaldehyde show similar reactivity for the CO2/H2 system. [ABSTRACT FROM AUTHOR]

The authors focus on the methylation of amines with carbon dioxide and hydrogen molecule (H2). They mention that two catalysts formed from ruthenium acetylacetonate [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl) ethane, enabled the conversion of carbon dioxide and carboxylic acid derivatives into N,N-dimethylaniline and N-methylaniline. They mention that methylation reaction with formamide and methanol formed intermediates, which then reduced to a methylated product.

Vielseitig und metallfrei: Benzothiophen ‐ Boronsäuren katalysieren die Reduktion tertiärer, sekundärer und primärer Amide durch ein Hydrosilan. In der Reaktion wird eine Vielzahl von funktionellen Gruppen toleriert. [ABSTRACT FROM AUTHOR]

Kohlendioxid kann zur selektiven reduktiven Methylierung sekundärer und primärer aromatischer und aliphatischer Amine verwendet werden. Vielfältige tertiäre Amine werden durch Einwirkung von CO2 und käuflichen Silanen in hohen Ausbeuten erhalten. Die Katalysereaktion toleriert Nitril ‐ , Olefin ‐ , Ether ‐ , Ester ‐ und Hydroxygruppen in den Substraten. [ABSTRACT FROM AUTHOR]

Zwei Eisenspezies im Team: Ein NAD(P)H ‐ Modell wird in einer eisenkatalysierten Reduktion mit molekularem Wasserstoff in situ regeneriert. Die anschließende biomimetische Reduktion von α ‐ Keto ‐ und α ‐ Iminoestern liefert in Gegenwart einer Eisen ‐ basierten Lewis ‐ Base (LA) α ‐ Hydroxy ‐ bzw. α ‐ Aminosäureester in guten bis exzellenten Ausbeuten (siehe Schema; NAD(P)+=Nicotinamidadenindinucleotid(phosphat), TM=Übergangsmetall). [ABSTRACT FROM AUTHOR]