2′ Modified oligonucleotides

Claim 1

An oligonucleotide having the formula: or a salt thereof, wherein: each B independently is a protected or unprotected purine or pyrimidine base in the β-anomeric configuration; W 3 and W 4 are each independently H, PO 3 −2 , a protecting group, or an intermediate moiety in the formation of an internucleotide link which when reacted with the appropriate —OH results in Z; n is an integer of 1-200; each Z is independently is P(O)O, P(O)S or P(O)N(R) 2 provided at least one Z is not P(O)O; each R is independently H or alkyl (C 1-6 ); each A is OCH 3 , H, OH, O—Pr wherein Pr is a protecting group, or X—Y wherein: X is O; and Y is substituted or unsubstituted alkyl (C 2-20 ) or substituted or unsubstituted alkenyl (C 2-20 ), wherein the substituents are a halogen, OH, NH 2 , SH, —O—, —CH 2 CONH 2 , —CH 2 COOCH 2 CH 3 , or CH 2 CONHCH 2 NH 2 ; and at least one A is OCH 3 .