Process for the preparation of beta-gamma ene carbonyl derivatives

A process for the preparation of a compound of formula (I)

• wherein:
• the dotted lines indicate that the compound is in the form of a mixture of the corresponding β-γ or α-β unsaturated derivatives, the molar ratio β-γ/α-β being at least 3;
• Y represents a OR4 or R4 group, R4 representing a C1-C8 hydrocarbon group, optionally comprising 1 to 3 heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen;
• R1 represents a C1-C15 hydrocarbon group, optionally comprising 1 to 3 heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen;
• R2 represents a C1-C5 hydrocarbon group, optionally comprising 1 to 3 heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen;
• and
• R3 represents a hydrogen atom or a C1-C5 hydrocarbon group;
• optionally wherein R1 and R2, or R1 and R3, taken together, form a C4-C12 hydrocarbon group optionally comprising 1 to 3 heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen;
• by a method which comprises:
• reacting, at a temperature between 100° C. and 230° C., a compound of formula
• wherein Y, R1, R2 and R3 are defined as in formula (I);
• with at least one compound from the group i) and at least one compound from the group ii) to prepare the compound of formula I, wherein:
• group i) includes a salts of formula MX2, M″X3 or M′X, wherein M is an alkali-earth cation and M′ an alkali cation or C0-C12 ammonium cation and M″ is a lanthanide cation, and X is a halide or an anion of an acid HX having a pKa comprised between 0 and 6;
• and
• group ii) includes carboxylic acids of formula R5COOH, wherein R5 represents a C1-C18 hydrocarbon group optionally comprising one or two oxygen atoms;
• and
• wherein the reaction is optionally conducted in the presence of a polar aprotic solvent having a boiling point of above 100° C.