Diazo Reagents in Copper(I)-Catalyzed Olefination of Aldehydes
作者:Hélène Lebel、Michaël Davi
DOI:10.1002/adsc.200800381
日期:2008.10.6
The olefination of aldehydes to synthesize unsaturated ketones, esters, amides and phosphonates using diazo reagents and triphenylphosphine in the presence of copper(I) iodide as catalyst, is described. Good to excellent E:Z selectivities as well as yields were obtained for a large variety of aliphatic, aromatic and heteroaromatic aldehydes. The reaction showed also an excellent functional group compatibility
The rhodium-catalyzed methylenation of aldehydes using trimethylsilyldiazomethane and triphenylphosphine produces a variety of terminal alkenes in excellent yields. These mild and nonbasic reaction conditions allow the conversion of enolizable substrates (keto aldehydes and nonracemic alpha-substituted aldehydes) to terminal alkenes without epimerization. Optimization of the reaction conditions led
Terminal alkenes have been efficiently prepared via a rhodium-catalyzed olefination procedure using Wilkinson’s catalyst in the presence of triphenylphosphine, 2-propanol and trimethylsilyldiazomethane. Optimized reaction conditions are described for aldehydes and ketones, as well as alternative work up procedures.