Airat M. Gimazetdinov

The synthesis of a bicyclic allyl acetate, a promising precursor of (–)-galiellalactone, is performed. The synthetic approach is based on separation of the diastereomeric carboxamides prepared by the amidation of racemic gem-dichloro-substituted Grieco lactone with (+)-α-methylbenzylamine. The subsequent steps of transformation of an individual diastereomer involve complete reductive dechlorination, construction of an allyl alcohol fragment in the ring part by stereo- and regiospecific bromohydroxylation with NBS in aqueous THF, and dehydrobromination.

The synthesis of bicyclic allyl acetate 2, a promising precursor of (-)-galileolactone 1, is described. The approach is based on the separation of diastereomeric carboxamides obtained by amidation of racemic gem-dichloro-substituted Grieco lactone with (+)-α-methylbenzylamine. Subsequent steps of transformation of an individual diastereomer include reactions of complete reductive dechlorination, construction of an allyl alcohol fragment in the ring part by stereo- and regiospecific bromohydroxylylation with NBS in aqueous THF, and dehydrobromination.

The synthesis of the exo-methylidenecyclopentenone amide given in the title of the article from the methyl ester 2-{(1R,2R,5R)-2-[((tert-butyl(dimethyl)silyloxymethyl]-5-(trimethylsilyl)cyclopent-3-en-1-yl}acetic acid.

With the goal of searching for new more chemically stable analogues (prodrugs), isomeric misoprostol (9E/Z)-oximes and individual 11α-acetoxy (9E)-O-acetyloxime derivative have been synthesized and characterized. The ratio of the E and Z oximes has been estimated at 10:1 on the basis of the oxime OH signal intensities in the ¹H NMR spectrum.

New vicinal all- cis -trisubstituted derivatives of cyclopentane- and cyclopentenetriols were synthesized.

The possibilities for preparing a series of exo-methylidencyclopentenones, from simple to close-to-natural, from an available chiral basic bicyclic γ-lactone, are considered. The structural features and stability, as well as biological and chemical properties of the synthesized compounds are discussed.

This paper described a first example of the application of the “abnormal” lactone of 3-oxabicyclo[3.3.0]oct-6-en-2-one topology in targeted prostaglandin synthesis.

The review covers the literature on the total synthesis of cross-conjugated cyclopentenone prostaglandins (PGs), published from 2000 until present. In view of the specific features differentiating...