Hydrochloric Acid → (6-Chloro-2-oxohexyl) triphenylphosphonium chloride

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Reaction Steps

The latter reactions are exemplified by the cleavage of δ-valerolactone with zinc chloride and thionyl chloride to produce 5-chlorovaleryl chloride, reaction of that acid chloride with diazomethane, followed by treatment of the resulting diazomethyl ketone with hydrochloric acid to yield 1,6-dichloro-2-hexanone, and reaction of that ketone with triphenylphosphine to afford (6-chloro-2-oxohexyl)triphenylphosphonium chloride. This product is converted to (5-chloropentanoylmethylene)triphenyl phosphorane by reaction with aqueous sodium hydroxide. Condensation of that phosphorane with the aforementioned 3α-(tetrahydropyran-2-yloxy)-2β-formyl-5-oxocyclopentane-1α-heptanoic acid affords a mixture of stereoisomers, which are separated by chromatographic techniques to afford, as the major product, 3α-(tetrahydropyran-2-yloxy)-2β-(7-chloro-3-oxo-1-heptenyl)-5-oxocyclopentane-1α-heptanoic acid. Removal of the tetrahydropyran-2-yl group is effected by reaction with acetic acid in aqueous tetrahydrofuran, thus affording 3α-hydroxy-2β-(7-chloro-3-oxo-1-heptenyl)-5-oxocyclopentane-1α-heptanoic acid.

Provenance & Evidence