Solid supports and phosphoramidite building blocks for oligonucleotide conjugates

A compound of Formula I:

• wherein:
• A and A1 are the same and are selected from —CH2— or —(CH2)2—;
• E and E1 are the same and are selected from —CH2— or —(CH2)2—;
• G is a substituted aliphatic or a substituted cycloaliphatic group having from 5 to 28 carbons and 1 to 5 substitutions, provided one substitution is a —C(═O)— that forms an amido group (—NHC(═O)—) with the ring nitrogen and wherein each of the other substitutions, if present, is independently —O—, —S—, —NH—, —SO2—, —NHC(═O)—, —C(—O)NH—, or a hydroxy group alkylated with either (i) optionally protected N-acetyl-D-galactosamine, or (ii) α-tocopherol;
• one of R and R1 is hydrogen, acetyl (“Ac”), bis-(4-methoxyphenyl)phenylmethyl (“DMT”), or tris-(4-methoxyphenyl)methyl (“TMT”), and the other of R and R1 is PA, or L1, wherein
• PA is
• and L1 is —C(═O)CH2CH2C(═O)—W,
• wherein W is a hydroxy group, a negatively charged atom of oxygen (O−), or a solid phase material selected from a controlled pore glass, aminopropyl controlled pore glass, magnetic controlled pore glass, polymers of styrene, copolymers of styrene and divinylbenzene, controlled pore glass grafted with polymers of styrene, controlled pore glass grafted with copolymers of styrene and divinylbenzene, copolymers of styrene and divinylbenzene grafted with polyethyleneglycol, or flat glass surface.