Aluminium lithium hydride → (R)-[1-(4-Benzyloxy-benzyl)-2-oxo-ethyl]-carbamic acid tert-butyl ester

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Reaction Steps

LiAlH4 (916 mg, 24.1 mmol) was added cautiously and portionwise during 15 min to a stirred solution of (R)-[2-(4-Benzyloxy-phenyl)-1-(methoxy-methyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester (10.00 g, 24.1 mmol) in THF (150 mL) at 0° C. under an atmosphere of argon. The ice-bath was removed and the mixture was stirred for 1 h, then poured onto a mixture of ice and KHSO4 (1M aqueous). When the ice had melted the product was extracted into EtOAc. The combined extracts were washed with brine then dried (Na2SO4) and evaporated to give the aldehyde as pale yellow crystals (8.51 g, 99%), mp 100.3-101.7° C. (lit. mp 98-99° C.).[W. J. Thompson et al, Tetrahedron Lett., 1990, 31, 6819] 1H NMR (CDCl3) δ 9.63 (1H, s, CHO), 7.45-7.33 (5H, m), 7.09 (2H, d, J=8.7 Hz), 6.92 (2H, d, J=8.6 Hz), 5.05 (2H, s, OCH2Ph), 4.40 (1H, br s, Hα), 3.07 (2H, d, J=6.7 Hz, Hβ,β), 1.44 (9H, s, CMe3). 13C NMR (CDCl3) δ 199.6, 156.4, 144.4, 136.8, 130.4, 128.6, 128.5, 128.0, 127.9, 127.5, 115.1, 80.9, 70.0, 46.0, 34.6, 28.3.

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