Tert-butyldiphenylsilyl (TBDPS) was found to be an effective orthogonal protecting strategy for the 5-substituted hydroxyl groups of de novo synthesized deoxyuridine analogues 1–3 and 7-(3-hydroxypropynyl)-of 8-aza-7-deazadeoxyadenosine 4 for their incorporation into oligodeoxynucleotides by phosphoramidite chemistry. It could be completely cleaved under normal and ultra-mild deprotection conditions applied to DNA synthesis, without extra ...