2-methyl substituted and 2-enoic fatty acids by Favorsky rearrangement of haloketones

✍ Scribed by Thomas Gerson; Hermann Schlenk

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 319 KB
• Volume: 2
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(68)90025-x

✦ Synopsis

Fatty acid chlorides were converted into haloketones via diazomethyl ketones. By treatment with alkali, chloromethyl ketones yielded 2-methyl substituted acids whereas a dibromomethyl ketone afforded a straight-chain acid unsaturated in the 2-position. 2-Methylpalmitic, 2-methylstearic and 2-methylarachidonic acids, and cis-2-nonadecenoic acid were prepared in yields ranging from 35-45 %.

The rearrangement of ct-haloketones to carboxylic acids, in the presence of alkali, was first described by Favorsky 1) and has been studied extensively 2). The reaction has hitherto not been utilized for the synthesis of longchain fatty acids although the appropriate haloketones are easily accessible 3, 4). This report describes the preparation of 2-methylpalmitic, 2-methylstearic and 2-methylarachidonic acids from the corresponding straight-chain fatty acids and that of cis-2-nonadecenoic acid from stearic acid using the Favorsky rearrangement.