Levulinic Acid Hydrogenation with Homogeneous Cu(I) Catalyst

Abstract

We report the first well-defined homogeneous copper-based catalyst for levulinic acid (LVA) hydrogenation using complex [(PPh 3 ) 2 Cu(k 2 -O,O-LVA)] as a copper source and (1,2bis(diisopropyl phosphino)ethane (dippe) as an ancillary ligand. This catalytic precursor has high activity in LVA hydrogenation and yields γ-valerolactone (GVL) under relatively mild reaction conditions (24 h, 140 °C) in a base-free system using H 2 (300 psi) as a reductant. Under optimized conditions, GVL was obtained with excellent yield (> 99 %) and selectivity (> 99 %) using a low catalytic load (0.025 mol %), allowing a TON = 4000.

Silver(I) and Copper(I) Complexes of Dicarboxylic Acid Derivatives: Synthesis, Characterization and Thermal Studies

“…The bis(triphenylphosphine) copper(I) complexes were prepared from the respective copper(II) carboxylates by reduction with Ph 3 P in wet MeOH (Scheme 3) [20,21]. Compound 8a has recently also been prepared from [Cu(PPh 3 ) 2 (NO 3 )] and levulinic acid in hexane; the reported spectroscopic data, however, are somewhat different to what we observe [22]. In contrast to the silver compounds, the copper counterparts could not be prepared from the reaction between the acid derivatives and copper(I) oxide.…”

Copper-driven formation of siloxanes via dehydrocoupling between hydrosilanes and silanols

“…7, part b ). 68–70 Once again, irrespective of the atmosphere, the reaction proceeded in the presence of mercury, indicating homogeneous catalysis.…”

Phosphine‐Free Bis(imino)pyridine‐Based Pincer Palladium(II) Complexes as Catalysts for C−H Bond Arylation of Azoles with Aryl Iodides

“…The yield of the catalytic reactions was not altered by the presence of metallic mercury which indicates the catalytic reactions are homogeneous in nature. [13] Based on the previous report on the arylation of azoles with aryl halides using palladium(II)-pincer complexes, [1b,8,14] a plausible mechanism is illustrated in Scheme 3. The reaction proceeds with the formation of azolyl-copper species 'A' from the reaction of azole with CuI in the presence of the base.…”