Synthesis of (5R*,6R*,7S*)-6-iodo-1,5,6,7-tetrahydro-4,1-benzoxazonin-3(2H)-ones

New 6-iodo-1,5,6,7-tetrahydro-3H-4,1-benzoxazonin-3-ones have been synthesized by reaction of N-tosyl- and N-(2-nitrobenzenesulfonyl)-N-[2-(alkenyl)phenyl]aminoacetic acids with molecular iodine.     

Combinatorial solution-phase synthesis of alkyl (1S*,2S*,3R*,5R*,6R*)-1-alkyl-3-aryl-6-benzoylamino-1-hydroxy-7- oxo-5-phenylhexahydropyrazolo[1,2-a]pyrazole-2-carboxylates

Combinatorial solution-phase cycloadditions of (1Z,4R*,5R*)-4-benzoylamino-5-phenylpyrazolidin-3-on-1-azomethine imines 3 to beta-keto esters 4 afforded a library of 26 bicyclic pyrazolidinones 5 in 6-89% yields and in 14-100% de. All products were isolated in >90% purity according to 1H NMR, and 25 of them were analytically pure. The structures of cycloadducts were confirmed by NMR and X-ray diffraction. Most of the products were isolated as mixtures of the major (1S*,2S*,3R*,5R*,6R*)-epimers 5 and the minor (1R*,2S*,3R*,5R*,6R*)-epimers 6. Epimerization of cycloadducts 5/6 at the anomeric position 1 in solution was confirmed by 1H NMR.     

Synthesis of (5S*,4aS*,7aS*)-5-hydroxyhexahydro-cyclopenta[c]pyran-3(1H)-one

(5S*,4aS*,7aS*)-5-Hydroxyhexahydrocyclopenta[c]pyran-3(1H)-one, the promising isoprostane building block, was synthesized using intramolecular [3+2] cycloaddition of silyl nitronate generated from 4-benzyloxy-3-nitroocta-2,7-diene on the key step.