68014-21-1

tert-Butyl (Triphenylphosphoranylidene)carbamate is used in the preparation of ketimines.

Step 1: Synthesis of triphenyl (tert-butoxycarbonylimino) orthophosphine 25 g (0.19 mol) of tert-butylhydrazinyl formate was dissolved in a mixed solution of 80 mL of acetic acid and 160 mL of water, and 15 g (0.22 mol) of sodium nitrite was added in batches under ice bath cooling conditions. The reaction solution was continuously stirred under ice bath cooling for 30 minutes and subsequently extracted with 250 mL of diisopropyl ether. The organic layer was washed sequentially with 200 mL of saturated aqueous sodium bicarbonate and 100 mL of saturated aqueous sodium chloride, dried over anhydrous sodium sulfate and filtered to give an ether solution of tert-butyl carbonate. To this ether solution was added 49.6 g (0.189 mol) of triphenylphosphine under cooling in an ice bath, and the reaction mixture was stirred at room temperature for 1 hour. The precipitated solid was collected by filtration and washed with water. 200 mL of hexane was added and dried under reduced pressure to give 67 g of the target product triphenyl(tert-butoxycarbonylimino)orthophosphine in the form of white crystals.

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[4] Patent: US2013/253204, 2013, A1. Location in patent: Paragraph 0196; 0197
[5] Patent: US9212348, 2015, B2. Location in patent: Page/Page column 169