Oligonucleotide analogs with dimethylenesulfide, -sulfoxide, and -sulfone groups replacing phosphodiester linkages

Two sets of experimental protocols are given for the synthesis of 3',5'-bis-homodeoxyribonucleosides, building blocks for the synthesis of oligodeoxynucleotide analogs where the -O-PO2-O- groups are replaced by -CH2-S-CH2-, -CH2-SO-CH2-, and -CH2-SO2-CH2- units. Conditions are presented for joining these building blocks to create short nucleic acid analogs. Since isosteric, achiral, and non-ionic analogs of natural oligonucleotides stable to both enzymatic and chemical hydrolysis, such molecules have potential application as probes in the laboratory, in studies of the biological function of individual genes, and as "antisense" oligonucleotide analogs.