Olefin participation in the acid-catalyzed opening of acylcyclopropanes. IV. Cyclization of 5-methyl-6-endo-(trans-3-pentenyl)bicyclo(3.1.0)hexan-2-one.

✍ Scribed by Gilbert Stork; Paul A. Grieco

• Book ID: 104238797
• Publisher: Elsevier Science
• Year: 1971
• Tongue: French
• Weight: 201 KB
• Volume: 12
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)87467-0

✦ Synopsis

Previous studies have shown that acylcyclopropsnes can undergo acldcatalyzed transformation with psrtlclpstlon of a suitably pla.ced double bond and formation of a new rlng(g. A-B). 2-4 We now report on a case(endoblcyclo(3.l.O)hexanone, I) in which the double bond undergoes 90$ olefln participation generating a c.vclohexyl catlonlc species which experiences either simple proton loss or hydride transfer leading to a new cation which either undergoes angular methyl migration or gets trapped by the enol. m *Lb + 0 0 A B The endo-blcyclo(3.1.O)hexanone I was synthesized from the dlenlc acet.al IV(vlde lnfra) by the usual sequence y& the aldehyde V, R=H, 'X(fllm) 3.70, 5..51, --lO.35p ; acid V, R=OH(sllver oxide oxidation),2 (film) 2.80-4.20, 5.85, 10.35fi; G(cDC13) 11.08(s, 1H); acid chloride V, R=Cl(thlonyI chloride/carbon tetrachloride), A(fllm) 5.53, 10.35~; and dlaeoketone V, R=CHN2, Z4(fllm) 3.25, 4.74, 6.05, 10.35r. Cycllzation of the latter(reflux with copper bronze in CyCIohexane) afforded the desired ketone I. I was homogeneous by gIPC(DECS, 190',