A Synthesis of lndane Musk Celestolide Shinzo Kagabu and Yuka Kojima Faculty of Education, Gifu University, Gifu 501-11,Japan
is a Celestolide, 4-acetyl-6-t-butyl-1,l-dimethylindane, commercial perfume component with an outstanding musk odor. The preproduct 6 has been prepared technically by acid-catalyzed addition of isoprene to tbutylbenzene (1).However, its annellation mechanism is too specific for a beginning course to adopt, and, besides, we encountered difficulty in isolating 6 purely from the concomitant isomers on a laboratory scale. In order to introduce the synthesis of the industrial product to the undergraduate laboratory, we have adapted an alternative multi-step preparation. (See figure.) The synthesis was designed so that inexperienced students can wmplete a sequence of experiments with conventional reagents and apparatus within a standard laboratory period, while learning some fundamental reaction types. The synthetic work starts with the benzylation of acetoacetic ester using potassium carbonate in refluxing ethanol. By this simple procedure, 2 was obtained in yields comparable to those from existing methods using sodium metauethanol (21, phase-transfer catalyzers like tetraalkylammonium salts (3)or crown ethers (4). or stronc bases in aorotic solvents (51.Together the hydrolysis of
