2-oxo-3-benzyl-4-methyl-7-vinyl-2H-1-benzopyrane → 2-Oxo-2H-chromene-7-carbaldehyde

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Reaction Steps

To the suspension of 2-oxo-3-benzyl-4-methyl-7-vinyl-2H-1-benzopyrane (16.0 g, Example 23) in dioxane (350 mL) and water (75 mL) is added osmium tetraoxide (1.45 mmol) in t-BuOH. The reaction mixture is stirred at room temperature for 30 minutes and sodium periodate (30 g) is added in portions. The solid is filtered out after 30 minutes stirring and the filtrate is partitioned between CH2Cl2 and water. Separation and the organic layer is washed further with H2O and dried over MgSO4. Evaporation of the organic solvent gives the desired 7-formyl coumarin intermediate (12.0 g).

Provenance & Evidence