Hydrolysis of cyclic phosphites/phosphoramidites (OCH2CRR'CH2O) PX [X= OPh (1), NMe2 (2)] in the presence of intentionally added water is effectively inhibited by using simple additives such as KF, K2CO3, Et3N, and molecular sieves. Among these, K2CO3 gave the best results. Cyclic H-phosphonates (OCH2CRR'CH2O) P (O) H (3), which are the tautomeric forms of the phosphites (OCH2CRR'CH2O) P (OH), undergo facile hydrolysis ...