Table of Contents
Research Letters in Organic Chemistry
Volume 2009 (2009), Article ID 528081, 5 pages
http://dx.doi.org/10.1155/2009/528081
Research Letter

Synthesis of Benzo[ 𝑏 ]fluorenone Nuclei of Stealthins

Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India

Received 3 December 2008; Accepted 16 February 2009

Academic Editor: Robert Strongin

Copyright © 2009 Sujit Kumar Ghorai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Two routes, one based on a Michael-initiated aldol condensation and the other on an intramoleculer carbonyl-ene reaction, have been found to be feasible for an entry to benzo[ 𝑏 ]fluorenones. Reaction of 4,9-dimethoxybenz[ 𝑓 ]indenone with nitromethane in the presence of DBU gave the corresponding Michael adduct, which afforded 2-methyl-5,10-dimethoxybenzo[b]fluorenone on reaction with methacrolein under a variety of basic conditions. Similarly, 2-methallyl-4,9-dimethoxybenz[ 𝑓 ]indenone reacted with nitromethane to give the corresponding Michael adduct, Nef reaction of which furnished 3-formyl-2-methyl-4,9-dimethoxybenz[ 𝑓 ]indanone. This underwent ene-cyclization under the influence of SnCl4. 5H2O, and yielded 2-methyl-5,10-dimethoxybenzo[ 𝑏 ]fluorenone.