Diastereoselective Spiroannulation of Phenolic Substrates: Advances Towards the Asymmetric Formation of the Manumycin m-C7N Core Skeleton

Molecules

Guy L. Plourde¹  Randy R. Spaetzel²  Jolene S. Kwasnitza² 

[1] id="af1-molecules-12-02215">University of Northern British Columbia, Department of Chemistry, 3333 University Way, Prince George, British Columbia, Canada, V2N 4Z9; Tel: [phone], Fax: [phone]

关键词: Spiroannulation;    oxidation;    phenol;    diastereoselective;    asymmetric;    Manumycins;    Aranorosins;    Gymnastatins;   

DOI  :  10.3390/12092215

来源: mdpi

【 摘 要 】

The asymmetric syntheses of two new spirolactones prepared in optically pure form from L-3-nitrotyrosine are described. The key step, an oxidative spiroannulation, was carried out on the optically active phenols 11a and 11b and afforded the new spirolactones 5a and 5b in 85% and 83% yields, respectively, as mixtures (3:1 dr) of diastereomers. The major diastereomers from these mixtures could be isolated in optically pure form by trituration using acetone-hexanes as the solvent. Thus, the optically active spirolactones (+)-5a (+ 92.8^o, c=0.125 acetone) and (+)-5b (+112.0^o, c= 0.125 acetone) were obtained after four synthetic steps from L-3-nitrotyrosine in 41% and 43% yield, respectively.

【 授权许可】

Unknown   
© 2007 by MDPI (http://www.mdpi.org).