Stereochemistry of internucleotide bond formation by the H -phosphonate method. 2. Transesterification of aryl ribonucleoside H -phosphonate diesters with alcohols
Aryl ribonucleoside 3’-H-phosphonates were used as model compounds in investigations of stereochemistry of an internucleotide bond formation. For all four ribonucleoside 3’-H-phosphonates studied the major diastereomers of the produced H-phosphonate diesters were found to be formed from the minor diastereomers of nucleoside aryl H-phosphonate diesters. These studies indicate the importance of an equilibrium between substrate diastereomers and can be relevant to the stereoselectivity observed in condensation reactions of ribonucleoside H-phosphonates promoted by condensing agents, e.g. pivaloyl chloride.