(1)-Alkyl-allyl ester prodn. - by isomerisation of (3)-alkyl-allyl ester in presence of copper carboxylic acid and anhydride

摘要

Prodn. of allyl esters (I) of the formula CH2=CH-CHR'-O-CO-R" (in which R' is 1-4C alkyl, opt. with an acyloxy substit. with max. 4C. alkyl or H) involves isomerisation of allyl esters (II) of the formula R'-CH=CH-CH2-O-CO-R" at elevated temp., as in DT 2406058, in the presence of Cu and/or Cu (I) or Cu (II) cpds. and in the presence of carboxylic acids (III). The improvement comprises the use of carbocylic anhydride (IV) in addn. to (III). (IV) pref. is the anhydride of (III), esp. acetic anhydride (IVa), and is used in an amt. of 0.1-10 mole-% wrt (III). In an example but-2-en-1,4-diyl acetate was isomerise to but-2-en-3,4-diyl acetate in the presence of (IVa) the yield being 10% and amt. of by-prods. 1%. If (IVa) was omitted, the yield was up to 2.5% and amt of by-prods. 1.5%. (I) are used as starting materials in organic syntheses.