Patent ID: 6919437

Claim:
A compound having the formula: wherein: each B is, independently, a naturally occurring or non-naturally occurring nucleobase; each R 1 is, independently, H, OH, F, or a group of formula R 7 —(R 8 ) n ; each R 7 is, independently, a diradical of C 3 -C 20 alkyl C 4 -C 20 alky, C 2 -C 20 alkynyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyloxy, or C 2 -C 20 alkynyloxy; each R 8 is, independently, hydrogen, amino, protected amino, halogen, hydroxyl, thiol, keto, carboxyl, nitro, nitroso, trifluoromethyl, trifluoromethoxy, O-alkyl, S-alkyl, NH-alkyl, N-dialkyl, O-aryl, S-aryl, NH-aryl, O-aralkyl, S-aralkyl, NH-aralkyl, N-phthalimido, azido, hydrazino, hydroxylamino, isocyanato, aryl, a radical derived from imidazole, polyamide, polyalkylene glycol, polyether, or a group of formula (—O—X 3 ) p1 , where p 1 is 2 to about 10 and X 3 is alkylene having from one to about 10 carbons or alkyl having form one to about 10 carbons; each X is, independently, O or S; R z is a divalent aromatic radical having about 5 to about 8 carbon atoms or has formula (CH 2 ) x3 ; z is 0 or 1; x 1 , x 2 , and x 3 are, independently, 1 to about 5; R L is —OH or —N(R N1 )(R N2 ); R N1 is H or alkyl having 1 to about 10 carbon atoms; R N2 is a solid support; and R 3 is hydrogen, a hydroxyl protecting group, or group of the formula: wherein: each X is, independently, O or S; Z 1 is H or a hydroxyl protecting group; n is 1 to about 100; m is 1 to about 100; and R n and R m are selected such that: each R n is, independently, O − or O—(CH 2 ) p2 —E and each R m is —Y 1 —(CH 2 ) q —Y 2 —Y 3 —Z; or each R n is —Y 1 —(CH 2 ) q —Y 2 —Y 3 —Z and each R m is, independently, O − or O—(CH 2 ) p2 —E; wherein: p2 is 1 to about 5; E is —CN; each Y 1 is O; each q is, independently, 2 to about 4; each Y 2 is, independently O or S; each Y 3 is, independently, C(═O) or S; and each Z is, independently, aryl having 6 to about 14 carbon atoms or alkyl having from one to about six carbon atoms; provided that at least one of x 1 and x 2 is not 1 when R 3 is hydrogen or a hydroxyl protecting group and z is 0, and provided that at least one nucleoside is a β-nucleoside and bound at its 3′ position to a linking group of formula —O—P(X)(R n )—O— or —O—P(X)(R m )—O— where R n or R m is O − or —O—(CH 2 ) p2 —E.