Application of intramolecular aza-[3 + 3] annulation to syntheses of Coccinellidae defensive alkaloids

ORGN 370

Aleksey I. Gerasyuto, gerasyuto@wisc.edu, Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, 777 Highland Avenue, Madison, WI 53705-2222 and Richard P. Hsung, rphsung@pharmacy.wisc.edu, Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin-Madison, 777 Highland Ave., Rennebohm Hall, Madison, WI 53705-2222.
Intramolecular aza-[3 + 3] annulation was shown to be a powerful tool in syntheses of various alkaloids such as gephyrotoxin, tangutorine, deplancheine and cylindricine C. Herein we report application of this tandem process to total syntheses of azaphenalene natural products. Cycloadduct precursor 2 was prepared in 5 steps from cis-disubstituted lactam 1 which is readily accessible from commercially available compounds. Intramolecular [3 + 3] annulation of aldehyde 2 leads to formation of tricycle 3 as a single diastereomer. Conversion of dihydroazaphenalene 3 to hippodamine and precoccinelline will be presented.

 

New Reactions and Methodology
8:00 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 133, Oral

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006