Synthesis of three new compounds structurally related to damascone and ionone

✍ Scribed by Jan G. Witteveen; Anton J. A. van der Weerdt

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 435 KB
• Volume: 100
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19811001009

✦ Synopsis

Abstract

1‐(3,6,6‐Trimethyl‐1,3‐cyclohexadien‐1‐yl)‐2‐buten‐1‐one (1), a β‐damascenone isomer, was synthesized from 3,6,6‐trimethyl‐2‐cyclohexenone (14). This starting ketone 14 was obtained in good yield from 3‐methyl‐2‐butanone (11) and 3‐buten‐2‐one (12). Ethynylation of 14 with 3‐butyn‐2‐ol afforded acetylenic diol 20. Acid‐catalyzed rearrangement of 20 yielded
1‐(3,6,6‐Trimethyl‐1‐cyclohexen‐1‐yl)‐2‐buten‐1‐one (2), a β‐damascone isomer, was prepared from 1 by hydrogenation. Ketone 2 is shown to be identical to a naturally occurring compound found in fusel oil.
4‐(3,6,6‐Trimethyl‐1‐cyclohexen‐1‐yl)‐3‐buten‐2‐one (3), a β‐ionone isomer, was obtained by condensation of 3,6,6‐trimethyl‐1‐cyclohexenecarboxaldehyde (29) with acetone. Aldehyde (29) was synthesized from 2,2,5‐trimethylcyclohexanone (16) by reaction of its tosylhydrazone 28 with n‐butyllithium and DMF.
The compounds 1–3, 17–21 and 25–29 are new. 1.