Synthesis of 2-Cycloalkenones (Parts of 1,4-Diacyl-1,3-butadiene Systems) and of a Heterocyclic Analogue by Metal-Catalyzed Decomposition of 2-Diazoacylfurans

✍ Scribed by Ernest Wenkert; Ming Guo; Ferdinando Pizzo; Kishore Ramachandran

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: German
• Weight: 725 KB
• Volume: 70
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19870700524

✦ Synopsis

Furans with side-chains at C(2) of various lengths terminating in diazomethyl keto groups are shown to undergo Rh*(OAc),-catalyzed furan unravelling with the production of 2-cyclopentenone, 2-cyclohexenone, and 2-cycloheptenone to each of whose olefinic C(p) is attached an acrylaldehyde unit. Interposition of a cyclohexane or a methylaminomethylene moiety between the furan and diazoketo functions leads to the formation of a hydroindenone and pyrrolone, respectively. Replacement of the diazomethylketo terminus by an cc-diazoethylketo system or a a-diazo-b-keto-ester function produces 2-substituted 2-cycloalkenones. A furan with a C,, diazomethylketo-terminating side-chain at C(3) is described to be transformed into a 4-formylmethylidene-2-cyclohexenone.

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