A method for preparing a compound of formula: wherein R1 represents a hydrogen atom, a phenyl radical or a linear or branched, saturated or unsaturated hydrocarbon-based radical containing 1 to 8 carbon atoms, R2 denotes a radical chosen from: - a linear, branched or cyclic, saturated hydrocarbon-based radical containing 1 to 12 carbon atoms, optionally substituted with 1 to 3 groups, which may be identical or different, chosen from -OR31, -NR31R41, -COOR31, -OCOR31 and halogens, with R31 and R41 representing, independently of one another, a hydrogen atom, a phenyl radical or a linear or branched, saturated or unsaturated alkyl radical containing 1 to 4 carbon atoms; - a radical -Ar-R22, with Ar being an aromatic ring chosen from phenyl or pyridyl groups, and R22 representing a substituent chosen from: hydrogen, -OR', -NO 2, halogens, -NH 2, -CF 3 and -R', with R' denoting a hydrogen atom, a linear, branched or cyclic, saturated or unsaturated hydrocarbon-based radical containing 1 to 6 carbon atoms, or a phenyl radical; - a radical -R23-Ph, wherein R23 represents a linear or branched, saturated or unsaturated hydrocarbon-based divalent radical containing 1 to 6 carbon atoms, optionally substituted with 1 to 3 -OH groups and/or optionally interrupted with 1 to 3 non-adjacent oxygen atoms; - a radical -R24-NH-R34, wherein R24 represents a linear or branched, saturated or unsaturated hydrocarbon-based divalent radical containing 1 to 4 carbon atoms, optionally substituted with 1 to 3 -OH groups and/or optionally interrupted with 1 to 3 oxygen atoms; R34 represents a substituent -COOR' or a linear or branched, saturated or unsaturated hydrocarbon-based radical containing 1 to 4 carbon atoms, optionally interrupted with an NH, O or S group, wherein R' represents a hydrogen atom, a linear, branched or cyclic, saturated hydrocarbon-based radical containing 1 to 6 carbon atoms, or a phenyl radical; - a radical -CO-O-R25, wherein R25 represents a hydrogen atom, a phenyl radical or a linear or branched, saturated or unsaturated hydrocarbon-based radical containing 1 to 8 carbon atoms; as well as the optical isomers, diastereomers and/or corresponding salts thereof; in which method the following steps are carried out: a) 1,4 addition to acrolein of an alkyne of formula R2C=CH with R2 as defined in formula above; b) cyclization of the product obtained at the end of step a) by intramolecular hydroacylation; c) 1,4 addition to the cyclopentenone resulting from step b) of the malonate derivative CH 2 (CO 2 CH 2 Ph) (CO 2 R0) for which, when in formula R1 is a hydrogen atom, then -R0 is -CH 2 Ph and when in formula R1 is not a hydrogen atom, then R0 is R1; d) reduction and decarboxylation of the product obtained in step c). - a linear, branched or cyclic, saturated hydrocarbon-based radical containing 1 to 12 carbon atoms, optionally substituted with 1 to 3 groups, which may be identical or different, chosen from -OR31, -NR31R41, -COOR31, -OCOR31 and halogens, with R31 and R41 representing, independently of one another, a hydrogen atom, a phenyl radical or a linear or branched, saturated or unsaturated alkyl radical containing 1 to 4 carbon atoms; - a radical -Ar-R22, with Ar being an aromatic ring chosen from phenyl or pyridyl groups, and R22 representing a substituent chosen from: hydrogen, -OR', -NO 2, halogens, -NH 2, -CF 3 and -R', with R' denoting a hydrogen atom, a linear, branched or cyclic, saturated or unsaturated hydrocarbon-based radical containing 1 to 6 carbon atoms, or a phenyl radical; - a radical -R23-Ph, wherein R23 represents a linear or branched, saturated or unsaturated hydrocarbon-based divalent radical containing 1 to 6 carbon atoms, optionally substituted with 1 to 3 -OH groups and/or optionally interrupted with 1 to 3 non-adjacent oxygen atoms; - a radical -R24-NH-R34, wherein R24 represents a linear or branched, saturated or unsaturated hydrocarbon-based divalent radical containing 1 to 4 carbon atoms, optionally substituted with 1 to 3 -OH groups and/or optionally interrupted with 1 to 3 oxygen atoms; R34 represents a substituent -COOR' or a linear or branched, saturated or unsaturated hydrocarbon-based radical containing 1 to 4 carbon atoms, optionally interrupted with an NH, O or S group, wherein R' represents a hydrogen atom, a linear, branched or cyclic, saturated hydrocarbon-based radical containing 1 to 6 carbon atoms, or a phenyl radical; - a radical -CO-O-R25, wherein R25 represents a hydrogen atom, a phenyl radical or a linear or branched, saturated or unsaturated hydrocarbon-based radical containing 1 to 8 carbon atoms; a) 1,4 addition to acrolein of an alkyne of formula R2C=CH with R2 as defined in formula above; b) cyclization of the product obtained at the end of step a) by intramolecular hydroacylation; c) 1,4 addition to the cyclopentenone resulting from step b) of the malonate derivative CH 2 (CO 2 CH 2 Ph) (CO 2 R0) for which, when in formula R1 is a hydrogen atom, then -R0 is -CH 2 Ph and when in formula R1 is not a hydrogen atom, then R0 is R1; d) reduction and decarboxylation of the product obtained in step c).