Stereoselective conversion of (+)cis-2-oxabicyclo[3.3.0]oct-6-en-3-one into methylR-(+)-7-(3-hydroxy-5-oxo-cyclopentenyl)-5-cis-heptenoate

Intermediates of Prostanoid Synthesis. Stereospecific conversion of (+)‐5β‐hydroxycyclopenten‐2‐yl‐1β‐acetic acid γ‐lactone into (+)‐1β‐methoxycarbonylmethyl‐2β,3β‐(p‐nitrobenzylidene)‐dioxycyclopentan‐5‐one

“…Hydroxylation of the lactone (1) was found to give (+)-2/?, 3/?,5/?-trihydroxycyclopentyl-1,8-acetic acid 7-lactone (2 a) with cis-oriented hydroxy gronps in respect to the lactone ring. No formation of the trans-isomer, as has been reported earlier [4], -was observed.…”

“…spectrum coupling constant 3J,,, (see Table 1) must correspond definitely to the cis-orientation of the two hydroxy groups with respect to the lactone ring. These resultas are in complete disagreement with the conclusions and the structure 3 postulated before [4]. As described in [4], diol 2a was converted into the dioxolane 4a.…”

“…These resultas are in complete disagreement with the conclusions and the structure 3 postulated before [4]. As described in [4], diol 2a was converted into the dioxolane 4a. The specific optical rotation and IR-spectra of the compound obtained agree with those reported in [4] for a similar derivative which is believed to be 5.…”

“…Hydroxylatiou of the lactoile 1 was performed with potassiinii chlorate (1.1 mole) in water in the presence of osmium tetroxide used as catalyst. Earlier, other authors [4] using sodium chlorate as oxidant in a similar reaction have beeii able to obtain a product to which structure 3 has been assigned. The diol 2a obtained by us had the same melting point as the racemate 3 [4]; its specific optical rotation value was close to that of "(+)3", but the IR-spectrum differed from the data given for 3 (see Experimental and [4]).…”

Synthesis of latanoprost diastereoisomers

“…Product (5) (a) Reduction of lactone. In a three-neck, round-bottom flask fitted with an addition funnel and inert atmosphere, a solution of lactone (5,8.0 g, 40.4 mmol) in absolute toluene (300 ml) was cooled to À78jC. Diisobutylaluminum hydride (37.7 ml 1.5M in toluene, 56.5 mmol) was added dropwise over a 30-min period.…”