A compound having Formula I: W-P LG (Formula I), wherein, W is: and P LG is: wherein, R 9 is O, S, C, S, C 1-6 alkyl, C 1-6 alkyl substituted with one or more hydroxyl groups, C 1-6 alkyl substituted with one or more halo groups; R 10 is OH, SH, C H, S H, C 1-6 alkyl, C 1-6 alkyl substituted with one or more hydroxyl groups, C 1-6 alkyl substituted with one or more halo groups, OBn, NHBn, or Z-Q, wherein Z is O, S, N, NH, C 1-6 alkyl, C 1-6 alkyl substituted with one or more halo groups, and Q is aryl, any nucleotide, non-nucleotide, or polynucleotide which can be naturally-occurring or chemically-modified; R 11 is S or O; R 12 is H, halo, C 1-6 alkoxyl, C 1-6 alkenyl, C 1-6 alkenyl substituted with one or more hydroxyl groups, C 1-6 alkenyl substituted with one or more halo groups, or -OR 15; R 13 is H, -OH -O-trityl, substituted -O-trityl, -O-pixyl (9-phenylxanthenyl), substituted-O-pixyl (9-phenylxanthenyl), S-pixyl (9-phenylxanthenyl), substituted S-pixyl (9-phenylxanthenyl), halo, C 1-6 alkoxyl, C 1-6 alkenyl, C 1-6 alkenyl substituted with one or more hydroxyl groups, C 1-6 alkenyl substituted with one or more halo groups, a phosphate group, a phosphodiester, or -OR 15; R 14 is O, S, CH 2, S=O, CHF, or CF 2; R 15 is H, triisopropylsilylOCH 2 -, tert-butyldimethylsilylOCH 2 -, triethylsilylOCH 2 -, trimethylsilylethylOCH 2 -, triisopropylsilyl-, tert-butyldimethylsilyl-, trimethylsilylethyl-, triethylsilyl-, optionally substituted trimethylsilyl-, and optionally substituted trimethylsilylOCH 2 -; and B is adenine, guanine, uracil, cytosine, thymine, inosine, xanthine, hypoxanthine, isocytosine, isoguanine, 2-aminoadenosine, 5-methylcytosine, 2,6-diaminopurine, phenyl, naphthyl, 3-nitropyrrole, 5-nitroindole, nebularine, pyridone, pyridinone or diflurotolyl. W is: and P LG is: R 9 is O, S, C, S, C 1-6 alkyl, C 1-6 alkyl substituted with one or more hydroxyl groups, C 1-6 alkyl substituted with one or more halo groups; R 10 is OH, SH, C H, S H, C 1-6 alkyl, C 1-6 alkyl substituted with one or more hydroxyl groups, C 1-6 alkyl substituted with one or more halo groups, OBn, NHBn, or Z-Q, wherein Z is O, S, N, NH, C 1-6 alkyl, C 1-6 alkyl substituted with one or more halo groups, and Q is aryl, any nucleotide, non-nucleotide, or polynucleotide which can be naturally-occurring or chemically-modified; R 11 is S or O; R 12 is H, halo, C 1-6 alkoxyl, C 1-6 alkenyl, C 1-6 alkenyl substituted with one or more hydroxyl groups, C 1-6 alkenyl substituted with one or more halo groups, or -OR 15; R 13 is H, -OH -O-trityl, substituted -O-trityl, -O-pixyl (9-phenylxanthenyl), substituted-O-pixyl (9-phenylxanthenyl), S-pixyl (9-phenylxanthenyl), substituted S-pixyl (9-phenylxanthenyl), halo, C 1-6 alkoxyl, C 1-6 alkenyl, C 1-6 alkenyl substituted with one or more hydroxyl groups, C 1-6 alkenyl substituted with one or more halo groups, a phosphate group, a phosphodiester, or -OR 15; R 14 is O, S, CH 2, S=O, CHF, or CF 2; R 15 is H, triisopropylsilylOCH 2 -, tert-butyldimethylsilylOCH 2 -, triethylsilylOCH 2 -, trimethylsilylethylOCH 2 -, triisopropylsilyl-, tert-butyldimethylsilyl-, trimethylsilylethyl-, triethylsilyl-, optionally substituted trimethylsilyl-, and optionally substituted trimethylsilylOCH 2 -; and B is adenine, guanine, uracil, cytosine, thymine, inosine, xanthine, hypoxanthine, isocytosine, isoguanine, 2-aminoadenosine, 5-methylcytosine, 2,6-diaminopurine, phenyl, naphthyl, 3-nitropyrrole, 5-nitroindole, nebularine, pyridone, pyridinone or diflurotolyl.