Patent ID: 7915241

Claim:
A process for the preparation of compounds of Formula 1 having a (5Z) configuration, wherein X represents a hydrogen atom, a hydroxy group or an OR 1 group, where R 1 , R 2 and R 3 may be the same or different and represent groups suitable for hydroxyl protection, and R 4 is a C 1-6 alkyl chain or a C 3-6 cycloalkyl group, optionally substituted with C 1-3 alkyl groups, comprising the steps of: (a) reacting a sulfone of Formula 5, possessing a (5E) or (5Z) configuration, wherein X represents a hydrogen atom, a hydroxyl group or an OR 1 group, where R 1 and R 2 may be the same or different and represent groups suitable for hydroxyl protection-and R 5 is a heterocyclic group comprising at least one heteroatom selected from among oxygen, nitrogen, phosphorus and sulfur, with an aldehyde of Formula 6, having an (R) or an (S) configuration at the carbon atom directly attached to the carbonyl group, wherein R 3 is a hydrogen atom or a group suitable for hydroxyl protection and R 4 is a C1-6 alkyl chain or a C3-6 cycloalkyl group, optionally substituted with C1-3 alkyl groups, in the presence of a strong base, in a solvent selected from the group consisting of hydrocarbons and ethers, and (b) optionally, in case the product obtained in step (a) represented by formula 1 in which R 1 , R 2 , and R 3 are the same or different and represent groups suitable for hydroxyl protection, and R 4 , is a C 1-6 alkyl chain or a C 3-6 cycloalkyl group, optionally substituted with C 1-3 alkyl groups, has a (5E) configuration, it is subjected to photoisomerization reaction to a compound represented by formula 1 in which R 1 , R 2 , and R 3 are the same or different and represent groups suitable for hydroxyl protection, and R 4 is a C 1-6 alkyl chain or a C 3-6 cycloalkyl group, optionally substituted with C 1-3 alkyl groups, having a (5Z) configuration, and (c) removing the protective groups, R 1 , R 2 and R 3 simultaneously or one after another, from the compound of formula 1 to obtain the compound of formula 1 in which X represents a hydrogen atom or R 1 group and R 1 , R 2 and R 3 represent a hydrogen atom.