What is "phosphoramidite"

n. (context chemistry English) Any of a class of organic compounds formally derived from a phosphite by replacing a >P-O-R with a >P-N2 group; used in the synthesis of nucleic acids etc

A phosphoramidite (RO)PNR is a monoamide of a phosphite diester. The key feature of phosphoramidites is their markedly high reactivity towards nucleophiles catalyzed by weak acids e.c., triethylammonium chloride or 1H- tetrazole. In these reactions, the incoming nucleophile replaces the NR moiety.