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We have achieved the synthesis of 1-aryl-2-substituted 4-oxoquinoline and 4-oxo-1,8-naphthyridine derivatives, which cannot be synthesized by known methods, via two useful synthons, 2-formyl-4-oxoquinoline and 2-methylsulfonyl-4-oxo-1,8-naphthyridine. We also succeeded in the synthesis of 1-aryl-3-fluoro-4-oxoquinoline by fluorocyclization of N-arylenaminone with Select-fluor ® and potassium carbonate in DMF in a one-pot procedure. To the best of our knowledge, this is the first synthesis of 3-fluoro-4-oxoquinoline derivatives. We confirmed that these protocols were mutually applicable to the synthesis of 4-oxoquinoline and 4-oxo-1,8-naphthyridine derivatives.

Spiro C-arylglycoriboside was synthesized in 21 steps via Pd(II)-catalyzed spirocyclization as a key reaction. Hemiketal was obtained in 47% overall yield from cis-2-butene-1,4-diol and spirocyclized with PdCl 2 (PhCN) 2 in dilute THF solution (0.01 M) to afford the 1,6-dioxaspiro[4.4]nonane skeleton in high yield. The spirocyclo adduct was transformed into spiro C-arylglycoriboside in five steps.

Various 2-substituted 4-oxoquinoline and 4-oxo-1,8-naphthyridine derivatives are prepared from the key intermediates (I) and (VIII), respectively.

The total synthesis of 2-deoxy-D-ribose (VIII) is achieved in 12 steps from L-(-)malic acid (I) via an unstable hemiacetal.

Optically active 2,6-dimethylcyclohexanone-2-carboxylate was prepared by PLE-catalyzed dealkoxycarbonylation of σ-symmetrical β-ketodiesters, which possess quartemary carbons at α- and α'-positions. Moreover, (-)-podocarpic acid was prepared in a short sequence from 2,6-dimethylcyclohexanone-2-carboxylate.

We achieved a total synthesis of 2-deoxy-D-ribose through intramolecular Pd(II)-catalyzed cyclization of aldehyde via an unstable hemiacetal intermediate as a key step.