Face-selective Diels-Alder reaction of (1R,5R)-3-cyano-6,6-dimethylbicyclo[3.1.1]hept-3-en-2-one: Total synthesis of xenitorins B and C

ORGN 153

Hsing-Jang Liu, hjliu@mx.nthu.edu.tw, Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan, Wen-Sheng Chang, d907414@oz.nthu.edu.tw, Department of Chemistry, University of National Tsing Hua, Hsinchu 300, Taiwan, and Kak-Shan Shia, ksshia@nhri.org.tw, Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan.
Under Lewis acid catalysis, the title compound 1 adds to various dienes at low temperature with a reasonable rate, with the yields of the resulting chiral adducts being optimal when zinc chloride was employed. In all cases, only products resulting from a si-face addition, as generally exemplified by 2, were observed. The regiochemistry of the adducts exclusively conforms to that predicted by the ortho- and para-rules. The fact that the nitrile group in 2 can be easily replaced by various electrophiles greatly enhances the utility of these highly functionalized Diels-Alder adducts in various total synthesis endeavors. An application of this newly developed method for the rapid construction of polycyclic chiral compounds has led to the total synthesis of xenitorins B (3) and C (4), representative members of a group of recently isolated antineoplastic marine sesquiterpenoids.

 

Asymmetric Reactions and Syntheses, Physical Organic Chemistry, Combinatorial Chemistry, Total Synthesis
8:00 PM-10:00 PM, Sunday, 26 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster

Division of Organic Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006