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.
We describe a cerium‐catalyzed aerobic oxidative ringexpansion for the expedient construction of synthetically challenging macrolactones under visible‐light conditions. Cyanoanthracene has been employed as co‐catalyst to accelerate the turnover of the cerium cycle leading to a fast conversion within 20 min of irradiation. Taking advantage of the high efficiency and operationally simple conditions
Pyridinium chlorochromate (PCC) has been found to be selective reagent for the oxidative cleavage of enol ethers to esters or keto lactones in high yields.
Direct Lactonization of Alkenols via Osmium Tetroxide-Mediated Oxidative Cleavage
作者:Jennifer M. Schomaker、Benjamin R. Travis、Babak Borhan
DOI:10.1021/ol035057f
日期:2003.8.1
A highly efficient, mild, and simple protocol is presented for the tandem OsO4-mediated oxidative cleavage/oxidative lactonization of alkenols to lactones. The protocol couples the OsO4-catalyzed oxidative cleavage of olefins with Oxone as the co-oxidant with the direct oxidation of aldehydes in alcoholic solvents to their corresponding esters.
Bicyclic β-Hydroxytetrahydrofurans as Precursors of Medium Ring Keto-Lactones
作者:Helena M. C. Ferraz、Luiz S. Longo
DOI:10.1021/jo0626109
日期:2007.4.1
The reaction of a series of cis-fused bicyclic beta-hydroxytetrahydrofurans with ruthenium tetraoxide, generated in situ from ruthenium trichloride and sodium periodate, afforded 9- and 10-membered keto-lactones in moderate to good yields, in a clean and straightforward fashion. The starting beta-hydroxyethers were obtained from the corresponding 3-alkenols by two alternative procedures, depending on their pattern of substitution: (a) epoxidation by dimethyldioxirane, followed by base-catalyzed cyclization of the resulting epoxyalcohol, and (b) thallium trinitrate-mediated cyclization of the 3-alkenols, a method already described by our group.