Patent ID: 6380437
Filing Date: 2002-04-30
Classification: C07C

Abstract:
Process for the preparation of an unsaturated 4,5-allene ketone, of the general formula I in whichR1 and R2 represent a hydrogen, saturated or unsaturated, branched or unbranched C1 to C20-alkyl, aryl or alkylaryl, and R1 and R2 together form a 5- or 6-membered ring, R3 and R5 represent hydrogen or a C1 to C4-alkyl and R4 represents a C1 to C4 alkyl, by reacting a tertiary propargyl alcohol of the general formula II in which R1, R2 and R3 have the abovementioned meaning, with an alkenyl alkyl ether of the general formula III in which R4, R5 have the abovementioned meaning, R6 represents a C1 to C4 alkylor a ketal of the general formula IVin which R4, R5 and R6 have the abovementioned meaning at temperatures of 40 to 200Â° C. without a solvent or in an inert organic solvent in the atmosphere or under a pressure of up to 100 bar, wherein an aliphatic sulfonic acid of the general formula V R7SO3Hâ€ƒâ€ƒV in whichR7 represents halogen, a branched or unbranched, optionally halogen-substituted alkyl having 1 to 20 C atoms or a cycloalkyl, or a sulfonic acid salt of the general formula VIR8SO3Mâ€ƒâ€ƒVI in whichR8=R7 and additionally represents an aryl or a substituted aryl and M represents a cation of an organic or inorganic base, is used as the process catalyst.