Preparation of alkyl 5-oxo-6-heptenoates, and novel intermediate for the preparation thereof

US5659070A · kind A · utility

Assignee

• BASF SE

Inventors

• Klaus Ebel · Lampertheim, DE
• Matthias Eiermann · Schifferstadt, DE
• Thomas Papkalla · Mannheim, DE

Key dates

• Filing date: Feb 1, 1996
• Grant date: Aug 19, 1997
• Expiry date: Feb 1, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C67/333
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing alkyl 5-oxo-6-heptenoates of the formula I ##STR1## where X and Y are hydrogen or methyl, and R.sup.1 is C.sub.1 -C.sub.8 -alkyl, by PA1 A) reacting 5-acetyl-2-norbornene with a dialkyl carbonate [CO(OR.sup.2).sub.2, where R.sup.2 is C.sub.1 -C.sub.4 -alkyl,] in the presence of a base to give an alkyl 3-(2-norbornen-5-yl)-3-oxopropionate II, PA1 B) reacting the ester II on the presence of a base with an unsaturated compound of the formula III ##STR2## where Z is CN or CO.sub.2 R.sup.3, where R.sup.3 is C.sub.1 -C.sub.4 -alkyl, and hydrolyzing the product of the reaction of compound II with compound III to a 5-(2-norbornen-5-yl)-5-oxopentanoic acid of the formula IV, PA1 C) esterifying the acid IV to give a 5-(2-norbornen-5-yl)-5-oxopentanoic ester of the formula V, and PA1 D) converting the ester V by thermal cleavage into an alkyl 5-oxo-6-heptenoate I. The invention also relates to intermediates for preparing the esters I, to the use thereof and to an improved process for preparing alkyl 3-(2-norbornen-5-yl)-3-oxopropionates.