title: 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, 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 yields. Under exceptionally mild conditions, these bicycles are converted to highly functionalized medium-sized rings through a Grob-type fragmentation.
authors.affiliation: Medicinal Chemistry Division, Indian Institute of Integrative Medicine (CSIR) , Sanatnagar, Srinagar-190005, India.
authors.forename: Bilal A
authors.initials: BA
authors.lastname: Bhat
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Maki
authors.forename: Elijah J
authors.initials: EJ
authors.lastname: St Germain
authors.forename: Pradip
authors.initials: P
authors.lastname: Maity
authors.forename: Salvatore D
authors.initials: SD
authors.lastname: Lepore
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D003516:Cycloparaffins / Q000138:chemical synthesis* / Q000737:chemistry*; D004952:Esters; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011188:Potassium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001643:Bridged Bicyclo Compounds; D002254:Carbonates; D003516:Cycloparaffins; D004952:Esters; D007783:Lactones; C037593:potassium carbonate; D011188:Potassium