Buffered acetolyses of .beta.-cyclooctatetraenylethyl brosylates. Isomerization to tetrahydroazulenoid products in response to homoallylic electron deficiency
Buffered acetolyses of .beta.-cyclooctatetraenylethyl brosylates. Isomerization to tetrahydroazulenoid products in response to homoallylic electron deficiency
Heterogeneous permanganate oxidations: Synthesis of medium ring keto-lactones via substituent directed oxidative cyclisation
作者:Jagattaran Das、Srinivasan Chandrasekaran
DOI:10.1016/s0040-4020(01)85664-7
日期:1994.1
Homoallyl alcohols 4a-b and 5a-b undergo smooth oxidative cyclisation to give the corresponding ring enlarged keto-lactones under heterogeneouspermanganateoxidation conditions.
Homoallylic alcohols 4a-d, easily accessible in two steps from cyclopropyl methyl ketone, underwent a highly regioselective reaction with singlet oxygen to yield gamma-hydroxyhydroperoxides 5a-d in 57-72% yield. Acid-catalyzed reaction of 5a-d with acetone, cyclopentanone, and cyclohexanone furnished 1,2,4-trioxepanes 8a-d, 9a-d, and 10a-d in good yields. Homoallylic alcohol 12 also underwent a highly regioselective photooxygenation to yield delta-hydroxyhydroperoxide 13 in 67% yield, which on reaction with acetone, cyclopentanone, and cyclohexanone, furnished 1,2,4-trioxocanes 16-18 in 41-55% yield.
LILLIE, T. S.;RONALD, R. C., J. ORG. CHEM., 1985, 50, N 25, 5084-5088