Preparation of polyenes

US5276209A · kind A · utility

Assignee

• BASF SE

Inventors

• Hagen Jaedicke · Ludwigshafen, DE
• Klaus Kaiser · Neustadt, DE
• Manfred Hamm · Osthofen, DE

Key dates

• Filing date: Jul 17, 1992
• Grant date: Jan 4, 1994
• Expiry date: Jul 17, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C2601/16
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

An improved process for the preparation of polyenes by the Julia reaction comprises carrying out the allylation of the anion of an allyl aryl sulfone generated a strong base, and the elimination of arylsulfinic acid to form a double bond in the same inert polar solvent which is immiscible with water, preferably in a ketone of the formula I EQU R.sup.1 --CO--R.sup.2 (I) where R.sup.1 and R.sup.2 are each straight-chain or branched alkyl of 2 to 4 carbons, or R.sup.1 and R.sup.2 together are tetramethylene or pentamethylene. The process is particularly important for the preparation of vitamin A derivatives. In the preparation of vitamin A aldehyde, for example, it is advantageous to use the same alkali metal alcoholate as strong base in both stages so that the conversion can be carried out as one-pot reaction.