Dihydroxyacetone → 2-(Benzylamino)-2-(6-(benzyloxy)-3,4-dihydronaphthalen-2-yl)propane-1,3-diol

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Reaction Steps

The intermediate, 6-(benzyloxy)-3,4-dihydronaphthalen-2-ylboronic acid, from previous step was dissolved in ethanol (400 mL, 7 mol). 1,3-Dihydroxy-2-propanone (6.22 g, 0.0690 mol) was added followed by benzylamine (7.54 mL, 0.0690 mol). The solution turned into a yellow suspension in 1 min. The mixture was stirred at r.t. for 2 hours under an atmosphere of nitrogen. The mixture was filtered. The filtrate was concentrated and the residue was dissolved in EtOAc/MeOH (300 mL/30mL), washed with saturated NaHCO3/water (50 mL/50 mL) and the aqueous layer was extracted with EtOAc (2×50 mL). The combined organic layers were washed with water (50 mL), brine, dried with Na2SO4, filtered, concentrated and dried in high vacuum to give a red-brown solid product as the first crop. The collected solid was dissolved in DCM-MeOH (50 ml/50 mL) and stirred at r.t. overnight under an atmosphere of nitrogen. The solution was concentrated. The residue was treated as the first crop with EtOAc-MeOH-aqueous NaHCO3 to afford the second crop of product (4.40 g, 15%). 1H NMR (CHLOROFORM-d) δ: 6.98-7.66 (m, 13H), 6.77 (br. s., 1H), 5.05 (br. s., 2H), 3.75-4.21 (m, 6H), 2.78 (m, 2H), 1.88-2.54 (m, 2H). MS (M+1): 416.0.

Provenance & Evidence