Base catalyzed reaction of heterocyclic bases with R-(+)-glycidol gives heteroarylpropane-2,3-diols which are functionalized to the 3-O-dimethoxytrityl-2-O-phosphoramidites. A dimethoxytrityl-glycidol is reacted with alkyl or aryl Grignard reagents and then phosphitylated to yield 1-O-dimethoxytrityl-2-phosphoramidites. These compounds can be used for combinatorial oligomer synthesis. (C) 1996 Elsevier Science Ltd