Stereoselective synthesis of bicyclic lactone derivatives via tandem intramolecular Rh(II) catalyzed C-H insertion/Ring Closing Metathesis (RCM) sequence

ORGN 87

Mark C. McMills, mcmills@ohio.edu, Department of Chemistry and Biochemistry, Ohio University, 380 Clippinger, Athens, OH 45701 and Jason H. Stengel, js164303@ohio.edu, Chemistry and Biochemistry, Ohio University, 380 Clippinger, Athens, OH 45701.
The synthetic strength of rhodium-mediated C-H insertion reactions is well documented. The structure of the products resulting from C-H insertion of vinyl-diazo moieties provides half of the olefin pairing needed for a metathesis reaction to occur. Completion of the tandem process is realized through a tethered olefin present in the acyclic precursor. Stereoselectivity in the Rh2(OAc)4 catalyzed intramolecular C-H insertion reaction of alpha-vinyl diazo-ester (1) provides both diastereomers in the formation of the 3,4-disubstituted dihydrofuranone moiety (2) (X=O, Y=CH2). Screening and utilization of alternative catalysts is projected to enhance selectivity and produce one major diastereomer. Investigation of nitrogen and carbon analogues is currently underway. The subsequent Ring Closing Metathesis (RCM) reaction is facile and efficient.

 

Heterocycles, Aromatics, Materials, Devices, Switches, Combinatorial Chemistry, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, 13 March 2005 Convention Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 14 March 2005 Convention Center -- Sails Pavilion, Sci-Mix

Division of Organic Chemistry

The 229th ACS National Meeting, in San Diego, CA, March 13-17, 2005