Annulation Reactions of Allenyl Esters: An Approach to Bicyclic Diones and Medium-Sized Rings
作者:Bilal A. Bhat、Samantha L. Maki、Elijah J. St.Germain、Pradip Maity、Salvatore D. Lepore
DOI:10.1021/jo501700c
日期:2014.10.3
approach to construct sterically congested bicyclo-alkenedione frameworks is reported. Under the action of potassium carbonate, α-sulphonyl cycloalkanones are added to functionalized allenyl esters, leading to a lactone intermediate that is subsequently reduced to initiate an intramolecular aldol cyclization to [3.2.1], [3.3.1], and [4.3.1] bicycles. Oxidation then affords bicyclic diones in good three-step
Efficient and Stereoselective Synthesis of Bicyclo[3.2.1]octan-8-ones: Synthesis and Palladium-Catalyzed Isomerization of Functionalized 2-Vinyl-2,3,3a,4,5,6-hexahydro-2,3-benzofurans
diastereoselective formation of 2-vinyl-2,3,3a,4,5,6-hexahydro-2,3-benzofurans. The products could be efficiently transformed into functionalized bicyclo[3.2.1]octan-8-ones by a palladium-catalyzed rearrangement reaction. In case of sulfone derivatives, this rearrangement proceeds with high stereospecifity to give exclusively the endo-configured diastereomers. The bicyclo[3.2.1]octane skeleton is present