Catalytic enantioselective tandem carbonyl ylide formation—intramolecular cycloaddition with unsaturated α-diazo-β,ε-diketo sulfones

The synthesis and 1,3-dipolar cycloaddition reactions of unsaturated α-diazo-β,ε-diketo sulfones 7 using chiral rhodium catalysts (up to 71.5:28.5 er) are described.

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7-(Phenylsulfonyl)-11-oxatricyclo[5.3.1.01,5]undecan-8-oneC16H18O4Ser = 71.5:28.5 (by chiral HPLC)[α]D25=+13.6 (c 1.0, CH2C12)Source of chirality: Rh (S)-valine-derived catalystAbsolute configuration: unknown

7-(Methylsulfonyl)-11-oxatricyclo[5.3.1.01,5]undecan-8-oneC11H16O4Ser = 66.5:33.5 (by chiral GC)[α]D25=+3.1 (c 1.05, CH2C12)Source of chirality: Rh (S)-valine-derived catalystAbsolute configuration: unknown