Patent ID: 7501505

Claim:
A method of synthesizing an oligonucleotide, comprising coupling a nucleoside or a nascent oligonucleotide having a free hydroxy or thiol group and a nucleoside phosphoramidite in the presence of a coupling agent, wherein the coupling agent is a compound represented by the following structural formula: wherein: p is 0 or an integer from 1 to 4; X 7 is O or S; R for each occurrence is selected from the group consisting of halo groups, optionally substituted aliphatic groups, —NR 11 R 12 , —OR 13 , —OC(O)R 13 , —C(O)OR 13 , cyano, optionally substituted aryl groups, optionally substituted heterocyclyl groups, —CHO, —COR 13 , —NHCOR 13 , optionally substituted aralkyl groups, and —SR 13 ; or two adjacent R groups taken together with the carbon atoms to which they are attached form a six membered saturated or unsaturated ring; R 11 and R 12 are each, independently, —H, an optionally substituted aliphatic group, an optionally substituted aryl group, an optionally substituted group; or together with the nitrogen to which they are attached form a 5 or 6-membered heterocyclic ring; and R 13 is an optionally substituted aliphatic group, an optionally substituted aryl group, or an optionally substituted aralkyl group, wherein suitable substituents for each of the optionally substituted aliphatic, alkyl, aralkyl, heterocyclyl and aryl groups include aryl groups, halogenated aryl groups, C1-C8 non-cyclic alkyl groups, C3-C8 cyclic alkyl groups, non-cyclic C1-C18 aliphatic ether groups, cyclic C3-C18 aliphatic ether groups, aromatic ether groups, benzyl, halogens, cyano, nitro, —S(non-cyclic C1-C18 aliphatic) groups, —S(cyclic C3-C18 aliphatic) groups, and —S(aromatic) groups.