Synthesis of novel heterocycles related to the dynemicin A ring skeleton

Studies directed towards the construction of the CDE ring framework of dynemycin A (1) are reported. A series of quinoline based dienophiles containing an activating group (e.g. 5, Scheme 1), reacted with acyclic dienes (e.g. 4, Scheme 1) in a Diels-Alder fashion under increased pressure to afford a variety of heterocyclic systems related to the CDE skeleton of dynemycin A. Reaction of dienophile 15 with cyclic diene 29 led to the novel hetereocycle 34 whereas attempted decarbonylation of 41 led to a novel rhodium-promoted intramolecular carbonylation of the terminal acetylene furnishing compound 43.