Molybdenum catalyzed deoxydehydration of aliphatic glycols under microwave irradiation

Lam, Paul M.; John, Alex

doi:10.1016/j.jorganchem.2023.122705

Cited by 5 publications

(3 citation statements)

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“…Aiming for commercial accessibility of DODH systems, MoO 2 (acac) 2 has been explored as a possible catalyst. 102 Under microwave irradiation in toluene and using triphenyl phosphine as a terminal reductant, 1-phenyl-1,2-ethanediol was converted to styrene at 170 °C in 40 minutes. Reductions of more challenging aliphatic diols were also realized in anisole.…”

Section: Discussionmentioning

confidence: 99%

Reactivity of metal dioxo complexes

Canote,

Kilyanek

2024

Dalton Trans.

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Section: Discussionmentioning

confidence: 99%

Reactivity of metal dioxo complexes

Canote,

Kilyanek

2024

Dalton Trans.

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“…Given the potential of dioxomolybdenum complexes in affecting the DODH reaction under relatively mild condition (<200  C) and the ease of steric and electronic modulation, we were interested in studying these complexes over other ancillary ligands. 40,41 Specifically, we sought to study dioxomolybdenum catalysts based on [ONNO] salan ligands in the DODH reaction. Such molybdenum complexes have found applications in a variety of other catalytic reactions, and more importantly the modular nature of ligand synthesis allows for facile tunability of steric and electronic properties.…”

Section: Scheme 1 Deoxydehydration Of Glycols To Olefinsmentioning

confidence: 99%

Molybdenum Catalysts based on Salan Ligands for the Deoxydehydration Reaction

Wagner,

Tang,

Wagner

et al. 2024

Preprint

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Dioxomolybdenum complexes based on salan ligands have been evaluated for their potential in catalyzing the deoxydehydration (DODH) reaction. The DODH reaction is a formal reduction that converts vicinal diols into olefins using an oxometal catalyst and a sacrificial reductant. The reaction holds enormous potential in transforming biomass-derived molecules into platform chemicals. This study evaluated 20 molybdenum complexes supported by salan ligands in the DODH reaction with the goal of establishing structure-activity relationships. Catalyst screenings were performed using styrene glycol as a model substrate and 1-10 mol% loading of the molybdenum complexes at 170 oC producing styrene in up to 54% yield. Aliphatic diols and meso-/R,R-hydrobenzoin were also converted to the corresponding alkenes in moderate to good yields that are comparable to previously reported molybdenum catalysts. A bio-derived glycol, (+)−diethyltartrate, could be converted to the alkene product (diethyl fumarate) in >98% yield using 10 mol% catalyst. A high yield of diethyl fumarate (78%) was also obtained with Na2SO3 (cheap, readily available, and benign) as reductant. Quite significantly, a 42% yield of diethyl fumarate was also obtained at a 1 mol% catalyst loading which represents a turnover number (TON) of 42; this is one of highest activity in a DODH reaction observed with molybdenum catalysts. The catalytic studies along with preliminary kinetic investigations reveal significant ligand effects: sterically bulky ortho-substituents and electron-withdrawing para-substituents on the phenol arms were found to enhance catalytic activity while a rigid phenyl as well as an ethylene backbone featuring a tertiary amine were observed to impede catalysis.

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“…Given the potential of dioxomolybdenum complexes in affecting the DODH reaction under relatively mild condition (<200 °C) and the ease of steric and electronic modulation, we were interested in studying these complexes over other ancillary ligands. 40,41 Specifically, we sought to study dioxomolybdenum catalysts based on [ONNO] salan ligands in the DODH reaction. Such molybdenum complexes have found applications in a variety of other catalytic reactions, and more importantly the modular nature of ligand synthesis allows for facile tunability of steric and electronic properties.…”

Section: Introductionmentioning

confidence: 99%