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Annulation reactions of allenyl esters: an approach to bicyclic diones and medium-sized rings.

ABSTRACT: A flexible approach to construct sterically congested bicyclo-alkenedione frameworks is reported. Under the action of potassium carbonate, ?-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 yields. Under exceptionally mild conditions, these bicycles are converted to highly functionalized medium-sized rings through a Grob-type fragmentation.

SUBMITTER: Bhat BA

PROVIDER: S-EPMC4184455 | biostudies-other | 2014 Oct

REPOSITORIES: biostudies-other

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