Cycloadditions of substituted 1,2-dimethylenecyclopentanes. — The influence of methyl groups on the rate of diels-alder reactions

✍ Scribed by Sustmann, Reiner ;Daute, Peter ;Sauer, Ralf ;Sommer, Angelika ;Trahanovsky, Walter S.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1989
• Tongue: English
• Weight: 836 KB
• Volume: 122
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19891220827

✦ Synopsis

The preparation of methyl-substituted 1,2-dimethylenecyclopentanes and their reactivity in (4 + 2) cycloadditions with a,&unsaturated carboxylic esters and nitriles is studied. In kinetic measurements the methyl groups show a moderately rate-enhancing effect. The results are compared with those for analogously substituted butadienes. Whereas 1,ldimethylbutadiene reacts with TCNE to form a mixture of(2 + 2) and (4 + 2) cycloadducts, the correspondingly substituted 1Jdimethylenecyciopentane gives only the (4 + 2) adduct.