We describe an easy method for the solid phase synthesis of 3'-modifie
d oligonucleotides. The general synthetic scheme involves the immobili
sation of 5'-DMTr-T to CPG via a sulfonate linker, oligonucleotide syn
thesis and subsequent basic treatment to afford 3'-modified oligonucle
otides containing a 2,3'-anhydronucleoside moiety. These compounds can
be readily transformed into 3'-substituted oligonucleotides such as 3
'-deoxy-3'-azido species. (C) 1997 Elsevier Science Ltd.