Reaction Steps
3′-O-[(tertbutyl)dimethylsilyl]-5′-O-[(tertbutyl)diphenylsilyl]-4′-C-formyl-2-deoxyuridine (10) (Yang et al; Tetrahedron Letters 1992, 33, 37–40.) (0.15 g, 0.25 mmol) was treated with Ph2CHNH2 (0.07 g, 0.37 mmol, 0.064 mL), glacial acetic acid (0.015 g, 0.26 mmol, 0.015 mL) and NaBH3CN (0.023 g, 0.37 mmol) in acetonitrile (1 mL) according to the procedure used for the preparation of compound (2). The title compound (11) was obtained as clear, viscous oil (0.13 g, 69%). δH(300 MHz, CDCl3) 8.02(1H, s, br, N3—H), 7.81(1H, d, H-6), 7.69–7.18(20H, m, Ph2CHNH, tBuSiPh2), 6.32(1H, dd, H-1′), 5.30(1H, d, H-5), 4.67(1H, s, Ph2CHNH), 4.61(1H, dd, H-3′), 4.02(1H, d, H-5′), 3.87(1H, d, H-5′), 2.69(1H, d, 4′-C—CH2), 2.53(1H, d, 4′-C—CH2), 2.37(1H, m, H-2′), 2.17(1H, m, H-2′), 1.10(9H, s, tBuSiPh2), 0.75(9H, s, tBuSiMe2), 0.01(6H, s, tBuSiMe2); ES +ve m/z 776(M+H)+.
