Methods for the preparation of oligonucleotides having bioreversible phosphate
blocking groups are disclosed. In one aspect, the present invention provides compounds
comprising a sequence of nucleotide units that includes a first segment having
at least one internucleoside linkage of formula:
and a second segment having at least one internucleoside linkage of formula:
wherein each of X, Y1, and Y2 is, independently, O
or S; q is 2 to about 4; Y3 is C(O) or S; and Z is aryl having
6 to about 14 carbon atoms or alkyl having from one to about six carbon atoms.
