A-Naphthyldiphenylmethyl ethers

The a-naphthyldiphenylmethyl ether was prepared to protect, selectively, the 5 -OH group in nucleosides. It is prepared from a-naphthyldiphenylmethyl chloride in pyridine (65% yield), and cleaved selectively in the presence of a p-methoxy-phenyldiphenylmethyl ether with sodium anthracenide, a (THE, 97% yield). The p-methoxyphenyldiphenylmethyl ether can be cleaved with acid in the presence of this group. 

Protection of primary hydroxyl groups. The 5 -hydroxyl groups of nucleosides can be protected as the a-naphthyldiphenylmethyl ether. The group is selectively cleaved reductively in the presence of a p-methoxytrityl protecting group by sodium anthracenide in THE (HMPT). Sodium naphthalenide is less selective. The a-naphthyldiphenylmethyl group is relatively stable toward the benzophenone radical anion, which readily cleaves /3,/3,/3-trichloroethyl groups. 

Naphthalene, 506, 533 Naphthalene-Lithium, 415 Naphthalene 1,2-oxide, 358 Naphthojfc] cyclobutene, 550 Naphthojh] -cyclopropene, 477, 478 Naphthols, 503 Naphtho [ 1,8-Ac] -pyiane, 85 1,4 Naphthoquinones, 187 1,5-Naphthoquinones, 170 N-(1-Naphthyl)acetamides, 3 a-Naphthyldiphenylmethyl chloride, 415 a-Naphthyldiphenylmethyl ethers, 415... 

---