Ru-Catalyzed Cross-Dehydrogenative Coupling between Primary Alcohols to Guerbet Alcohol Derivatives: with Relevance for Fragrance Synthesis

Abstract

A simple method has been developed for the cross dehydrogenative coupling between two different primary alcohols using readily available RuCl(PPh) as a precatalyst through the borrowing-hydrogen approach. The present methodology is applicable to a large variety of alcohol derivatives including long chain aliphatic alcohols and heteroaryl alcohols. In addition, the methodology was applied in a straightforward protocol to synthesize commercially available fragrances such as Rosaphen and Cyclamenaldehyde in good yields.

Iron-Catalyzed Ligand Free α-Alkylation of Methylene Ketones and β-Alkylation of Secondary Alcohols Using Primary Alcohols

“…Though several indirect approaches have been established for such α,α-disubstituted branched products, they often require multistep synthesis and expensive alkyl halides in combination with highly acidic or basic conditions and generate stoichiometric halide waste. However, direct utilization of readily available biomass-derived renewable alcohols for such an alkylation process represents one of the most sustainable approaches that releases water as byproduct. , Nevertheless, to date, often alkylation of ketone enolates using alcohols is limited to the linear ketone products; however direct access to branched ketones utilizing enolate alkylation remains a challenging goal and is much less developed (Scheme ). α,α-Disubstituted branched ketones are an integral part of many bioactive molecules and are used as important building blocks in organic synthesis …”

Ir(NHC)‐Catalyzed Synthesis of β‐Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure

“…Various homogeneous transition‐metal catalysts have been reported for transition metal‐catalyzed β‐alkylation of alcohols via the BH strategy. Iridium, ruthenium, palladium, iron, copper, manganese, cobalt, and nickel catalysts were employed for cross‐coupling of secondary and primary alcohols [6–37] . For the condensation of primary alcohols (Guerbet reaction), iridium, rhodium, ruthenium, and manganese catalysts were employed [5,38–49] .…”

MOF-Derived RuCo Catalyzes the Formation of a Plasticizer Alcohol from Renewable Precursors

“…Given the compositional and structural diversity of MOFs, we set out to investigate if the in situ alloy formation between pore-incorporated ruthenium compounds and metals con-stituting MOF secondary building units (SBUs) could be generalized in order to access highly active Guerbet catalysts displaying complementary starting material selectivity relative to RuNi@MOF and thus be amenable to furnish high-volume chemicals such as 2-ethylhexanol from renewable precursors (Figure 1). To this end, we were pleased to find that the cobalt-based MOF Co II 4 O(1,4-bis[(3,5-dimethyl)pyrazol-4-yl]-benzene) 6 (MFU-1) 24,25 can, after pore incorporation of a commercially 7,21,22,26,27,29,30 The overall TOF was color-coded according to the fraction of 1-butanol converted into the respective reaction products. Loading of Ru on catalyst supports (in wt %) a 0.…”

“…Comparison of catalytic performance of different Guerbet catalysts in butanol upgrading in the presence of 10 (a) or 5 mol % (b) NaOBu at 170 °C [phen = phenanthroline and dppm = bis­(diphenylphosphino)­methane]. ,,,,,, The overall TOF was color-coded according to the fraction of 1-butanol converted into the respective reaction products. Loading of Ru on catalyst supports (in wt %) a 0.2 b 1.8 c 3.4 d 1.1 (see Figures S20–S21 and Tables S3–S4 for details).…”