Development of palladium(II) catalyzed macrocyclization reactions

ORGN 531

Craig A. Merlic, merlic@chem.ucla.edu, Juan M. Fernandez, almestar@chem.ucla.edu, and Daniel G. Chan, dgchan@chem.ucla.edu. Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, CA 90095-1569
An efficient and operationally practical strategy for macrocyclizations producing diene containing macrocycles was developed using pinacol vinylboronate esters and palladium(II) catalysis. When ?,?-vinylboronates were treated with catalytic PdCl2(PPh3)2 and chloroacetone as the re-oxidant in high dilution, formation of macrocyclic dienes was successfully achieved. For example, 14-, 15- and 16-membered E,E-diene macrocycles were obtained in good yields and as single geometrical isomers. Extensions to include Z,Z-diene macrocycles, carbonylation to divinyl ketones, and alkyne insertion to macrocyclic trienes will be described. Overall, this protocol is synthetically more efficient than a typical palladium(0) catalyzed coupling of end-group differentiated substrates containing both electrophilic and nucleophilic moieties.

 

Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Organic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007