Isopropanol → Isopropyl-N,N,N',N'-tetraisopropylphosphorodiamidite

Participants

Reaction Conditions

Reaction Steps

Bis(diisopropylamino)chlorophosphine (19, 250.1 g, 937 mmol) was dissolved in anhydrous ethyl ether (3.6 L) and triethylamine (190 g, 1.87 mol) was introduced. The turbid mixture was cooled at 0° C. and a solution of 2-propanol (225 g, 287 mL) in ether (200 mL) was added via a funnel. The resulting cloudy mixture was stirred at room temperature for 5.5 hours. The reaction was complete by checking with 31P NMR (δ=116.10 ppm, S). White solid (triethylamine HCl salt) was removed by filtration. The filtrate was concentrated to furnish a pale brown liquid (272 g, quantitative) and used for next step without further purification. Note that the P(III)-reagent can be purified by vacuum distillation (bp 84-86° C., 5 mm Hg) if desired to furnish a colorless clear oil. 1H NMR (CDCl3): δ 3.91 (m, 1H), 3.51 (m, 4H), 1.19 (d, 6H, J=6 Hz), 1.16 (24H, m). 31P NMR (CDCl3): δ 116.1.

Provenance & Evidence