Ammonium fluoride → Ethyl 8-allyl-6-(trifluoromethoxy)-2-(trifluoromethyl)-2h-chromene-3-carboxylate

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Reaction Steps

To a mixture of ethyl 8-iodo-6-(trifluoromethoxy)-2-(trifluoromethyl)-2H-chromene-3-carboxylate prepared as in Example 21a, Step 2 (1.00 g, 2.07 mmole) and Pd(PPh3)4 (0.239 g, 0.207 mmole) in anhydrous toluene (50 mL) under a dry N2 atmosphere was added tributylallyltin (0.707 mL, 2.28 mmole). The mixture was refluxed for 16 h and 20% NH4F solution (50 mL) was added. The mixture was stirred for 1 h and extracted with EtOAc (200 mL). The extract was washed with brine (100 mL), dried over Na2SO4, filtered and concentrated in vacuo. Purification by silica chromatography (9:1 hexanes:EtOAc) gave 0.770 g (94% yield) of the product as a yellow oil: EIHRMS m/z 396.0769 (M+, C17H14F6O4, Calc'd 396.0796).

Provenance & Evidence