Process for preparing 2-oxo-1-pyrrolidine derivatives by intramolecular allylation

A process for the preparation of compounds of general formula (I)

• wherein
• R2 and R3 are the same or different and each is, independently, hydrogen, C1-4 alkyl, cyano, aryl, —COOR7, halogen, R8COO—, R9SO3O— or R10SO2O—;
• R1 is Ra, Rb or C2-20 alkenyl optionally substituted by aryl;
• X is —CONR11R12, —COOR13 or —CN;
• R7, R8, R9 and R10 are each independently chosen from hydrogen, Ra′ and Rb′;
• R11, R12 and R13 are the same or different and each is, independently, hydrogen, C1-4 alkyl, aryl, arylalkyl, heteroaryl or heterocycloalkyl;
• Ra and Ra′ each independently represent C1-20 alkyl or C1-20 alkyl substituted by one or more halogen, hydroxy, thiol, amino, nitro, cyano, thiocyanato, carboxy, sulfonic acid, Rb, alkylsulfonyl, arylsulfonyl, alkylsulfinyl, arylsulfinyl, alkylthio, arylthio, alkoxy, aryloxy, sulfonamide, acyl, ester, amido, azido, acyloxy, esteroxy and/or amidooxy;
• Rb and Rb′ each independently represent aryl, heterocycloalkyl, heteroaryl or the same substituted by one or more halogen, Ra, hydroxy, thiol, amino, nitro, cyano, thiocyanato, carboxy, sulfonic acid, aryl, alkylsulfonyl, arylsulfonyl, alkylsulfinyl, arylsulfinyl, alkylthio, arylthio, alkoxy, aryloxy, sulfonamide, heterocycloalkyl, heteroaryl, acyl, ester, amido, azido, acyloxy, esteroxy and/or amidooxy;
• comprising the cyclisation of an intermediate of general formula (II)
• wherein
• Y is a leaving group selected from halogen, —OC(O)R14, —OSO2—R15 and —OClO3;
• R14 and R15 represent halogen or alkyl, arylalkyl, aryl, each optionally substituted by one or more halogen, alkyl, nitro and/or tertiary amino group;
• X1 is as defined for X;
• W is an electron withdrawing group selected from —COOR4, —COMe, —CN, —PO(OEt)2, —SO2aryl, —COaryl;
• R4 represents hydrogen, C1-6 alkyl, aryl, arylalkyl, wherein each aryl and arylalkyl may be substituted by one or more halogen, nitro, and/or methoxy;
• in the presence of one or more organic and/or inorganic bases.