Isomerization versus Decarboxylation of Protonated Oxetanone: Comparison between Experimental Results and Theoretical Calculations

✍ Scribed by Prof. Dr. Gregorio Asensio; Prof. Dr. Miguel A. Miranda; Dr. Julia Perez-Prieto; Maria J. Sabater; Dr. Antonio Simóon-Fuentes

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 260 KB
• Volume: 29
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199011461

✦ Synopsis

The use of alcohols as nucleophiles necessitates the consideration of further reaction pathways in addition to those discussed above, since, besides ketones and tautomeric enols, small equilibrium concentrations of enol ethers and acetals may also be present.['61 However, acetals and enol ethers need not be intermediates in the umpolung reaction, as shown by treatment of 2-(p-rnethoxyphenyl)cyclohexanone (11, E, = 1.63 V) with 200 mol Yo of 9 @ in pure acetonitrile: 12 is formed in 74% yield [Eq. (c)]. ' 11 12 -co\ / G o , I H,C=CH, "'

The investigations show that ketones such as 1 and 5, which exhibit a low tendency toward enolization, can be methoxylated in the c t position via their enol radical cations. It is still unclear how the enol radical cations react further to give the products." 7i Elucidation of the mechanistic details and scope of application of this novel umpolung reaction of ketones, especially in comparison with known methods,llsi is in progress.