Benzylamine → (R)-N-benzyl-1-(2,2-dimethyl-1,3-dioxolan-4-yl)methanamine

関与物質

反応手順

The title compound was prepared in the same way as that method described for preparing the (S)-enantiomer (M. Lemaire, F. Posada, J.-G. Gourcy and G. Jeminet, Synlett, 1995, 627). A solution of (S)-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl methanesulfonate (3.0 g, 14.27 mmol) and benzylamine (6.23 ml, 57.1 mmol) were refluxed together in CH3CN (38 ml) for 48 h. Tlc (EtOAc-hex 8:2) showed a new product (uv/molybdate or ninhydrin) with Rf ˜0.3 together with a little higher running sm. The solvent was evaporated and the residue dissolved in EtOAc and washed with aqueous sat. NaHCO3, dried and the solvent evaporated. The residue was chromatographed (EtOAc-hex, 6:4 then 8:2) to give (R)—N-benzyl-1-(2,2-dimethyl-1,3-dioxolan-4-yl)methanamine (2.56 g, 11.57 mmol, 81% yield) as a yellow oil. [α]D21 −3.7 (c, 0.885, CHCl3). 1H NMR (CDCl3, 300 MHz), δ ppm, 7.32-7.20 (m, 5H), 4.25, (m, 1H), 4.03 (dd, 1H, J 8.0, 6.4 Hz), 3.82 (s, 2H), 3.68 (dd, 1H, J 8.0, 6.8 Hz), 2.74 (d, 2H, J 5.7 Hz), 1.40 (s, 3H), 1.35 (s, 3H). 13C NMR (CDCl3, 75.5 MHz), δ ppm, 140.6, 128.8, 128.4, 127.3, 109.5, 75.8, 67.9, 54.4, 52.1, 27.3, 25.8.

情報源と証拠