thylsilyl)oxy]-5-{[(tert-butyldimethylsilyl)oxy]methyl}oxolan-2-yl]-9H-purin-6-amine (23)
Following method D with 20 (80 mg, 97 μmol, 1.00 eq) and 1-bromobutane, 23 (40 mg, 47%) was obtained a