Oxorhenium Complexes as Aldehyde‐Olefination Catalysts
- 1 December 2004
- journal article
- research article
- Published by Wiley in Chemistry – A European Journal
- Vol. 10 (24), 6313-6321
- https://doi.org/10.1002/chem.200400296
Abstract
Several oxorhenium compounds in the formal oxidation states V and VII are examined as catalysts for the aldehyde‐olefination starting from diazo compounds, phosphines, and aldehydes. Of these, [ReMeO2(η2‐alkyne)] complexes provide the simplest catalysts to study, although [ReOCl3(PPh3)2] still remains the most efficient rhenium catalyst for aldehyde‐olefination described to date. Prior to the reaction with the Re catalysts the phosphine and the diazo compound react to form a phosphazine. No catalytic reaction occurs in cases where no phosphazine formation is observed. The first step of the catalytic cycle involves the formation of a carbene intermediate by the reaction of phosphazine and catalyst under extrusion of phosphine oxide and dinitrogen. In a second step the carbene reacts with aldehyde under olefin formation and catalyst regeneration. Excess of alkyne as well as the presence of ketones slows down the catalytic reaction. The olefination of 4‐nitrobenzaldehyde with diazomalonate is possible with these Re catalysts. In contrast, this reaction does not take place either in the classical Wittig fashion from Ph3PC(CO2Et)2 and aldehyde or by use of all other catalysts for aldehyde olefination reactions reported to date. Catalytic ylide formation from diazo compounds seems therefore not to be the only pathway through which catalytic aldehyde‐olefination reactions can proceed.This publication has 70 references indexed in Scilit:
- Highly selective organometallic ruthenium catalysts for aldehyde olefinationJournal of Catalysis, 2004
- Catalytic Activity of a New Ruthenium−(Trimethylsilyl)diazomethane ComplexOrganometallics, 2004
- General and Selective Olefination of Aldehydes and Ketones Catalyzed by a Cobalt(II) Porphyrin ComplexOrganometallics, 2003
- Efficient and Stereoselective Synthesis of β-Trifluoromethyl α,β-Unsaturated Esters via Iron(III) Porphyrin-Catalyzed Olefination of KetonesThe Journal of Organic Chemistry, 2003
- [ReO3(bipy)]+[X]−‐Catalyzed Aldehyde Olefination: Carbene and Phosphorane IntermediatesChemistry – A European Journal, 2003
- Iron Porphyrin-Catalyzed Olefination of Carbonyl Compounds with Ethyl DiazoacetateOrganometallics, 2003
- (η2-Alkyne)methyl(dioxo)rhenium Complexes as Aldehyde-Olefination CatalystsJournal of the American Chemical Society, 2003
- Methylenation of Aldehydes: Transition Metal Catalyzed Formation of Salt-Free Phosphorus YlidesAngewandte Chemie, 2001
- Lewis base adducts of bis-(halogeno)dioxomolybdenum(VI): syntheses, structures, and catalytic applicationsJournal of Molecular Catalysis A: Chemical, 2000
- Molybdenum metalloazines. New reagents for carbon-carbon double bond formation by an organometallic analog of the Wittig reactionJournal of the American Chemical Society, 1986