Patent ID: 7897795

Claim:
A process for preparing a prostaglandin analogue of formula (11) wherein R 1 represents H, C 1 -C 5 -alkyl, or benzyl; X represents CH 2 , O, or S; Z represents O or NH; and R′ represents C 2 -C 4 -alkyl; phenyl optionally substituted by halogen, C 1 -C 5 -alkyl, C 1 -C 4 -alkoxy, CF 3 , C 2 -C 4 -polyhaloalkyl, or C 1 -C 3 -aliphatic acylamino; 5- or 6-membered heterocycle containing one or more hetero atoms selected from a group consisting of nitrogen, oxygen and sulfur; C 3 -C 7 -cycloalkyl; or C 3 -C 7 -cycloalkenyl; the process comprises steps of: (a) converting a compound of formula (4): to a compound of formula (5): wherein R 2 represents a hydroxy-protecting group; (b) esterifying and deprotecting the compound of formula (5) to give a compound of formula (6): (c) converting the compound of formula (6) to a compound of formula (8): wherein R 3 represents a hydroxy-protecting group; (d) reacting the compound of formula (8) with a compound of formula (9): to give a compound of formula (10): wherein Y represents a metal complex, R″ represents a hydroxy-protecting group; and (e) converting the compound of formula (10) to give the compound of formula (11).