Date of Award
Doctor of Philosophy
Richard C. Larock
Additions of organometallic reagents to vinylic epoxides have become useful synthetic reactions for preparing allylic alcohols when the regio- and stereochemistry of the products can be controlled. Analogous organometallic processes employing alkenyl 2-azetidinones have never been reported in the literature. The results presented in this dissertation are the first observed examples of alkenyl 2-azetidinones reacting with organometallic reagents and organic halides to afford 3-alkenamides. The scope and limitations of these reactions are discussed;The palladium-promoted cross-coupling of alkenyl 2-azetidinones with aryl- and vinylmercurials provides a high yielding route to functionally-substituted 3-alkenamides. The 3-alkenamides are isolated as mixtures of E- and Z-isomers. Catalytic amounts of palladium can be employed in the reaction of cupric chloride and oxygen are used to reoxidize the palladium;The palladium-catalyzed cross-coupling of alkenyl 2-azetidinones with aryl and vinylic halides also produces the corresponding di- or trisubstituted 3-alkenamides. The arylation of alkenyl 2-azetidinones proceeds in high yield and is both regio- and stereo-selective. The vinylation of alkenyl 2-azetidinones, however, affords the corresponding substituted 3-alkenamides in low yield;The palladium-promoted cross coupling of vinylic epoxides and oxetanes with various aryl and vinylic halides and triflates has also been explored. The corresponding allylic or homoallylic alcohols are isolated in good to high yield as mixtures of stereoisomers with preferential formation of E-isomers.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Ding, Shuji, "Palladium-promoted cross-coupling of alkenyl heterocycles with organomercurials, organic halides and triflates " (1992). Retrospective Theses and Dissertations. 10108.