An efficient synthesis of the antisecretory prostaglandin enisoprost

Furan as a Building Block in Synthesis

“…Mechanistically, this rearrangement probably proceeds through tautomerization to (71), subsequent electrocyclic ring opening (72), and, finally, an intramolecular vinylogous aldol reaction. Interestingly, the rearrangement to cyclopentenones also succeeds directly with furfuryl alcohols, as shown by Dygos et al [41] Thus, the reaction of (74) with zinc(@ chloride in water producesprobably via the intermediates (75) and (76)the cyclopentenone (77). This was used for the synthesis of a prostaglandin derivative.…”

Furan as a Building Block in Synthesis

“…Mechanistically, this rearrangement probably proceeds through tautomerization to (71), subsequent electrocyclic ring opening (72), and, finally, an intramolecular vinylogous aldol reaction. Interestingly, the rearrangement to cyclopentenones also succeeds directly with furfuryl alcohols, as shown by Dygos et al [41] Thus, the reaction of (74) with zinc(@ chloride in water produces -probably via the intermediates (75) and (76) -the cyclopentenone (77). This was used for the synthesis of a prostaglandin derivative.…”

Li–X-type zeolite mediated Michael addition of thiols to cyclic enones and its application in the synthesis of 13-thiaprostaglandins

“…However, Li-X-type zeolite catalyst gave Michael addition product and formation of such rearranged product could be avoided. The required enone 22 (Scheme 4) was prepared from methyl 8-oxooctanoate as reported in literature [14][15][16]. Michael addition of thiols 9-11 to enone 22 resulted in formation of 13-thiaprostaglandins 23-25 (60-80% yields).…”