Ru-catalyzed oxidation of substituted acetylenes to α-keto esters and α-keto amides with iodosylbenzene

✍ Scribed by Paul Müller; José Godoy

• Publisher: Elsevier Science
• Year: 1982
• Tongue: French
• Weight: 194 KB
• Volume: 23
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)88651-7

✦ Synopsis

Oxidation of alkynyl ethers and -amines with iodosylbenzene in presence of Rucatalysts affords a-keto esters and a-keto amides in 44-84% yield. These conversions can also be effected with RuO,. Oxidations based on iodosylbenzene are of current interest in connection with model studies for peroxidases and cytochrome P-450.' Preparative applications in catalytic and uncatalyzed systems have been reported with PhIO,' but also Ph102.3 We have previously found that PhIO in conjunction with Ru-catalysts is an efficient reagent for conversion of alcohols to aldehydes, ketones or carboxylic acids.2a Disubstituted acetylenes are converted to a-diketones in yields of 65-86%, while terminal acetylenes are cleaved to carboxylic acids.4 We have applied the combination of PhIO/Ru-catalyst to 1-alkynyl ethers and 1-alkynyl amines to obtain the corresponding a-keto esters and amides in fair to excellent yield, depending on the substituents present in the substrate: R-C=C-OR' 0 R-CiC-R' R' 'R' RuC12(PPh& 0

The results are summarized in Tables 1 and2.