| abstract |
A process of making oligoribonucleoside and deoxyribonucleoside boranophosphates and salts thereof is disclosed. The process comprises the steps of condensing a ribonucleotide or deoxyribonucleotide with a nucleoside phosphitylating agent, wherein the phosphitylating agent includes a 5' -OH group protected by an acid-labile protecting group and a moiety bonded to the phosphorus atom therein that is a stronger proton acceptor than the 5'-OH group of the ribonucleotide or deoxyribonucleotide to form a reaction intermediate, then oxidizing the reaction intermediate so formed with a compound comprising a Lewis base and a boron-containing substituent, wherein the Lewis base is a weaker electron donor than the phosphite phosphorus of the reaction intermediate, to form a ribonucleotide or deoxyribonucleotide boranophosphate. These steps are repeated on the nucleotide boranophosphate to form an oligonucleotide boranophosphate. |