Diisopropylamine → 2-Cyanoethyl N,N-diisopropylchlorophosphoramidite

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Reaction Steps

Chemistry FIG. 11 illustrates the synthesis of diphosphitylating and triphosphitylating reagents (6 and 7). Phosphorus trichloride (21, 20 mmol) was reacted with 3-hydroxypropionitrile (22, 1 eq) to yield 2-cyanoethylphosphorodichloridite (23). The subsequent reaction of 23 with diisopropylamine (20 mmol, 1 eq) afforded 2-cyanoethyl diisopropylphosphoramidochloridite (24). Addition of water (1 eq) gave the intermediate 25 that was reacted with 24 (1 eq) or 23 (0.5 eq) to yield the diphosphitylating (26, 97%) and triphosphitylating (27, 94%) reagents, respectively. The chemical structures of 26 and 27 were determined by nuclear magnetic resonance spectra (1H NMR, 13C NMR, 31P NMR) and high-resolution time of flight electrospray mass spectrometry. Stability studies using spectroscopic methods showed that the compounds remained stable even after two weeks storage at −20° C.

Provenance & Evidence