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Abstract
The catalytic iron-mediated ene carbocyclization of triene ethers provides a useful new method for the stereoselective preparation of functionalized cyclopentanes. In this thesis the full details of our initial studies concerning the factors which are found to be important in the stereoselective and regioselective carbocyclizations of 2,7,9-decatriene ethers to form five-membered carbocyclic ring systems are described. The sense and degree of simple diastereoselection is dependent upon the (2E/2Z)-alkene geometry, the structure of the tether chain, and the nature of the ether protecting group.
(2E,7E)-Undecatriene ether substrates give rise to five-membered ring products in which the two newly formed stereocenters have the cis relative stereochemistry. (2Z,7E)-Undecatriene ether substrates generally give rise to the stereoisomeric product, that is, a cyclopentane possessing the trans relative stereochemistry. Undecatrienes possessing a non-chelating substituent adjacent to either the diene or the alkene functionalities cyclize with high 1,2-stereoinduction in such a manner that the resident center and the newly formed stereocenter have the trans relative stereochemistry.
The application of this carbon-carbon bond construction via the iron-catalyzed carbocyclization toward the enantioselective syntheses of two simple iridoid monoterpene lactones is described.
