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Aerobic Oxidation of Primary Aliphatic Alcohols to Aldehydes Catalyzed by a Palladium(II) Polyoxometalate Catalyst
Author(s) -
Barats Delina,
Neumann Ronny
Publication year - 2010
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200900663
Subject(s) - chemistry , polyoxometalate , dehydrogenation , catalysis , alcohol oxidation , ligand (biochemistry) , aldehyde , palladium , reactivity (psychology) , organic chemistry , autoxidation , alcohol , medicinal chemistry , photochemistry , medicine , biochemistry , receptor , alternative medicine , pathology
A hexadecyltrimethylammonium salt of a “sandwich” type polyoxometalate has been used as a ligand to attach a palladium(II) center. This Pd‐POM compound was an active catalyst for the fast aerobic oxidation of alcohols. The unique property of this catalyst is its significant preference for the oxidation of primary versus secondary aliphatic alcohols. Since no kinetic isotope effect was observed for the dehydrogenation step, this may be the result of the intrinsically higher probability for oxidation of primary alcohols attenuated by steric factors as borne out by the higher reactivity of 1‐octanol versus 2‐ethyl‐1‐hexanol. The reaction is highly selective to aldehyde with little formation of carboxylic acid; autooxidation is inhibited. No base is required to activate the alcohol. The fast reactions appear to be related to the electron‐acceptor nature of the polyoxometalate ligand that may also facilitate alcohol dehydrogenation in the absence of base.