Monomers and oligonucleotides comprising cycloaddition adduct(s)

A compound of formula I, or pharmaceutically acceptable thereof:

• wherein:
• X is O, S, NRN or CRP2;
• B is independently for each occurrence hydrogen, optionally substituted natural or non-natural nucleobase, optionally substituted triazole or optionally substituted tetrazole;
• NH—C(O)—O—C(CH2B1)3, NH—C(O)—NH—C(CH2B1)3;
• where B1 is halogen, mesylate, N3, CN, optionally substituted triazole or optionally substituted tetrazole;
• R1, R2, R3, R4 and R5 are each independently for each occurrence H, OR6, F, N(RN)2, N3, CN, -J-linker-N3, -J-linker-CN, -J-linker-C≡R8, -J-linker-cycloalkyne, -J-linker-RL, -J-Q-linker-RL, -J-linker-Q-RL, -J-linker-Q-linker-RL, -J-linker-J-Q-RL, or -J-linker-J-Q-linker-RL;
• J is independently for each occurrence absent, O, S, NRN, OC(O)NH, NHC(O)O, C(O)NH, NHC(O), NHSO, NHSO2, NHSO2NH, OC(O), C(O)O, OC(O)O, NHC(O)NH, NHC(S)NH, OC(S)NH, O—N═CH, OP(N(RN)2)O, or OP(N(RN)2);
• R6 is independently for each occurrence hydrogen, hydroxyl protecting group, optionally substituted alkyl, optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted aralkyl, optionally substituted alkenyl, optionally substituted heteroaryl, polyethyleneglycol (PEG), a phosphate, a diphosphate, a triphosphate, a phosphonate, a phosphonothioate, a phosphonodithioate, a phosphorothioate, a phosphorothiolate, a phosphorodithioate, a phosphorothiolothionate, a phosphodiester, a phosphotriester, an activated phosphate group, an activated phosphite group, a phosphoramidite, a solid support, —P(Z1)(Z2)—O-nucleoside, —P(Z1)(Z2)—O-oligonucleotide, —P(Z1)(Z2)-formula (I), —P(Z1)(O-linker-Q-linker-RL)—O-nucleoside, P(Z1)(O-linker-RL)—O-nucleoside, —P(Z1)(O-linker-N3)—O-nucleoside, P(Z1)(O-linker-CN)—O-nucleoside, P(Z1)(O-linker-C≡R8)—O-nucleoside, P(Z1)(O-linker-cycloalkyne)-O-nucleoside, —P(Z1)(O-linker-Q-linker-RL)—O-oligonucleotide, P(Z1)(O-linker-RL)—O-oligonucleotide, P(Z1)(O-linker-N3)—O-oligonucleotide, —P(Z1)(O-linker-CN)—O-oligonucleotide, P(Z1)(O-linker-C≡R8)—O-oligonucleotide, P(Z1)(O-linker-cycloalkyne)-O-oligonucleotide, —P(Z1)(-linker-Q-linker-RL)—O-nucleoside, —P(Z1)(-linker-Q-RL)—O-nucleoside, —P(Z1)(-linker-N3)—O-nucleoside, P(Z1)(-linker-CN)—O-nucleoside, P(Z1)(-linker-CR8)—O-nucleoside, P(Z1)(-linker-cycloalkyne)-O-nucleoside, —P(Z1)(-linker-Q-linker-RL)—O-oligonucleotide, —P(Z1)(-linker-RL)—O-oligonucleotide, P(Z1)(-linker-N3)—O-oligonucleotide, —P(Z1)(-linker-CN)—O-oligonucleotide, P(Z1)(-linker-C≡R8)—O-oligonucleotide or P(Z1)(-linker-cycloalkyne)-O-oligonucleotide;
• RN is independently for each occurrence H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted aralkyl, optionally substituted heteroaryl or an amino protecting group;
• RP is independently for each occurrence H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted cycloalkyl or optionally substituted heteroaryl;
• Q is absent or independently for each occurrence
• X1 is O, S, CF2, or CH2;
• Y1, Y2 and Y3 are each independent CRP, N, O, or S;
• W1 is CH or N;
• R100, R200, R300 and R400 are each independently hydrogen, halogen, ORN, CRP2, acyl, phosphonyl, sulfonyl;
• or alternatively, R100 and R200 or R300 and R400 are taken together to form an aryl, substituted aryl, heteroaryl, substituted heteroaryl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl;
• RL is hydrogen or a ligand;
• R8 is N or CR9;
• R9 is H, optionally substituted alkyl or silyl;
• and
• Z1 and Z2 are each independently for each occurrence O, S or optionally substituted alkyl;
• provided that at least one of R1, R2, R3, R4 and R5 is -J-linker-Q-RL, -J-linker-Q-linker-RL, -J-linker-J-Q-RL, or -J-linker-J-Q-linker-RL.