Lithium borohydride → (S)-benzyl 5-(hydroxymethyl)-2,3-dihydro-1H-inden-2-ylcarbamate

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Reaktionsschritte

(S)-methyl-2-(benzyloxycarbonylamino)-2,3-dihydro-1H-indene-5-carboxylate (15.37 mmol, 5.00 g) was dissolved in THF (50 mL) and the vessel purged with nitrogen. Lithium Borohydride (2M, 30.7 mmol, 15.37 mL) was added dropwise followed by methanol (30.7 mmol, 0.985 g). The solution was stirred at room temperature for 6 h before additional lithium borohydride (2M, 15.35 mmol, 7.69 mL) was added. Stirring was continued overnight. A further amount of lithium borohydride was added (2M, 15.35 mmol, 7.69 mL) and stirring continued for 1 h. The reaction was quenched with MeOH then water and concentrated to a light brown residue. This was partitioned between EtOAc (150 mL) and 1N HCl (150 mL) and the phases mixed and separated. The aqueous layer was twice extracted with ethylacetate and combined organics dried, filtered and concentrated to give a brown gum which was dissolved in MeOH (100 mL) and stirred with activated carbon. Filtration through a dicalite pad followed by concentration and purification on silica eluting with 0-2% MeOH/DCM gave (S)-benzyl 5-(hydroxymethyl)-2,3-dihydro-1H-inden-2-ylcarbamate as a beige solid (2.2, 48%). 1H NMR (400 MHz, CDCl3) δ 1.66 (t, 1H) 2.81 (m, 2H) 3.28 (m, 2H) 4.52 (bs, 1H) 4.65 (d, 2H) 4.95 (bs, 1H) 5.09 (bs, 2H) 7.15-7.37 (bm, 8H).

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