Reaction Steps
Pure 62 (100 mg, 0.128 mmol) was dissolved in THF (7 ml), cooled to 0° C. and added 1 M LiOH (1.3 ml, 10 equiv.). The reaction mixture was allowed to slowly reach r.t. When LCMS confirmed full conversion of 62 to 63, the reaction was neutralized with 1 M HCl satd. with NaCl (1.3 ml), diluted with DCM (20 ml) and brine (10 ml). Layers were separated and the aqueous layer was extracted with DCM (2×20 ml). Comb. organic layers were dried (Na2SO4), filtered and the solvent removed in vacuo to afford a clear oil (63)2 (quantitative yield). Rf=0.49 (Eluent: EtOAc). ESI-MS m/z found 552.2 ([M1-1]+, calcd 552.1); 1H-NMR (CDCl3, 400 MHz): 8.64 (1H, s, N—H), 8.44 (1H, s, Adenin), 7.95 (2H, d, J=7.1 Hz, Bz), 7.50 (1H, t, J=7.3 Hz, Bz), 7.40 (1H, t, J=7.3 Hz, Bz), 7.07-6.79 (5H, m, OBn), 6.11 (1H, s, H-1′), 4.66 (1H, d, J=11.5 Hz, CH2), 4.61 (1H, d, J=11.5 Hz, CH2), 4.48 (1H, d, J=1.8 Hz, H-2′/H-3′), 4.30 (1H, d, J=11.9 Hz, CH2), 4.12 (1H, d, J=11.9 Hz, CH2), 4.07 (1H, d, J=1.8 Hz, H-3′/H-2′), 4.02 (1H, d, J=8.6 Hz, CH2), 3.94 (1H, d, J=8.6 Hz, CH2), 3.02 (3H, s, OMs); 13C-NMR (CDCl3, 100 MHz): δ 165.31, 152.03, 150.45, 148.54, 141.99, 135.38, 132.90, 132.84, 128.63, 128.37, 128.26, 127.98, 127.88, 121.34, 87.90, 86.16, 79.84, 76.29, 73.45, 72.51, 67.76, 64.47, 37.48 (OMs). 2Compound 63 is also described in JACS 124, p. 2164-2176 (2002) but not as an isolated product.
