this invention is related to nucleic acid chemistry and describes novel 1 , 2 - dithiolane functionalized nucleoside phosphoramidites and corresponding solid supports . in addition to these derivatives , 1 , 2 - dithiolane moiety can also be functionalized to at the various positions of the nucleobase and sugar part as shown in schemes 1 to 8 . the nucleosides of our invention carry a primary hydroxyl for dmtr function for chain elongation . furthermore , the phosphoramidite function is attached at the 3 ′- hydroxyl of the nucleoside . this allows oligonucleotide chain extension under standard dna and rna synthesis chemistry conditions and techniques , thus leading to high quality oligonucleotides . these derivatives are useful for introduction of reactive thiol groups either at 3 ′- or 5 ′- end of the oligonucleotides on the solid supports such as gold , silver and quantum dots .