Patent ID: 8742143

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 comprise a step of converting a compound of formula (8′): to the compound of formula (11), wherein R 3 represents hydrogen or a hydroxyl protecting group.