Low temperature equilibration of cyclopropanes by Lewis acid catalysis

✍ Scribed by Hans-Ulrich Reissig; Ingrid Böhm

• Book ID: 104216995
• Publisher: Elsevier Science
• Year: 1983
• Tongue: French
• Weight: 211 KB
• Volume: 24
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)81506-3

✦ Synopsis

Under the influence of Lewis acids the cis/trans-equilibration of methyl 2-trimethylsiloxy cyclopropanecarboxylates occurs even at -78'C. It involves the heterolytic cleavage of a C-C bond and seems to be governed by steric effects. Usually cis-trans-isomerization of cyclopropanes involves homolytic cleavage of one bond 1 yielding 1,3-diradicals . The high temperature of more than 400°C necessary to induce this process in 1,2-dideuteriocyclopropane 2 can be lowered to about 50°C if geminal "capto-dative" 3 substituted cyclopropanes like (I) are chosen

. We here want to demonstrate that vicinal