Tetrabutylammonium Fluoride → (S,E)-N-(8-Hydroxy-2-methyloct-5-en-4-yl)-P,P-diphenylphosphinic amide

Participants

Reaction Steps

To a solution of the TBDPS-protected alcohol 8c (700 mg, 0.983 mmol, crude) in dry THF (8 mL) at 0° C. was added TBAF (1.0M/THF, 1.23 mL, 1.23 mmol), and the reaction mixture was allowed to warm to rt while stirring under argon. As completion was not reached after 4 h, 0.75 eq of TBAF (0.75 mL) was added at 0° C. The reaction mixture was stirred further at rt for 3 h, then quenched with sat. aq. NH4Cl and diluted with EtOAc. The aqueous phase was separated and extracted with EtOAc. The combined organic layers were washed with brine, dried (Na2SO4), filtered and concentrated in vacuo. Flash chromatography (SiO2, 95:5, EtOAc/MeOH) afforded 272 mg (77%, 2 steps) of the title compound as a white solid. mp 124.0-124.2° C.; [α]D23−12.1 (c 1.0, DCM); 1H NMR (300 MHz, CDCl3) δ 8.00-7.83 (m, 4H), 7.58-7.35 (m, 6H), 5.52 (dd, 1H, J=15.3, 9.0 Hz), 5.24 (m, 1H), 4.58 (bs, 1H), 3.78-3.47 (m, 3H), 2.80 (appdd, 1H, J=9.2, 3.8 Hz), 2.16 (m, 2H), 1.68 (bs, 1H), 1.55-1.43 (m, 1H), 1.43-1.31 (m, 1H), 0.87 (dd, 6H, J=8.6, 6.4 Hz); HRMS (ESI) m/z calcd for C21H28NO2PNa 380.1755; found 380.1725.

Provenance & Evidence