3,4-dihydro-2H-pyran → 8-(tetrahydro-pyran-2-yloxymethyl)-3,4-dihydro-2H-naphthalen-1-one

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Reaction Steps

The diol (Intermediate H3) (2.42 g, 13.5 mmol) was dissolved in CH2Cl2 (75 mL) and reacted with dihydropyran (1.3 mL, 13.8 mmol) and pyridinium para-toluene sulfonate (PPTS) (350 mg, 1.36 mmol) at rt for 18 h. The mixture was concentrated onto SiO2 and purified by chromatography with 10% EtOAc:Hx. The tetrahydropyranyl (THP) protected alcohol (2.02 g, 7.70 mmol) was dissolved in CH2Cl2 (10 mL) and added to a mixture of pyridinium chlorochromate (PCC) (4.9 g, 22.2 mmol), sodium acetate (310 mg, 3.56 mmol) and celite (˜10 g) in CH2Cl2 (100 mL). The mixture was reacted at rt for 18 h and filtered through celite. The residue was purified by chromatography on SiO2 with 20 to 30% EtOAc:Hx to yield 8-(tetrahydro-pyran-2-yloxymethyl)-3,4-dihydro-2H-naphthalen-1-one (Intermediate H4) (˜55%).

Provenance & Evidence