Hypervalent Iodine-Based Activation of Triphenylphosphine for the Functionalization of AlcoholsThis work was supported by the University of Waterloo and the Natural Sciences and Engineering Research Council (NSERC) of Canada (Discovery Grant 418602-2013).
Received: 18 April 2017
Accepted after revision: 06 June 2017
12 July 2017 (eFirst)
Dedicated to Professor Victor Snieckus on the occasion of his 80th birthday
The use of hypervalent iodine reagents as a general tool for the activation of PPh3 and its application to the functionalization of alcohols is reported. Combination of PPh3 with PhICl2 or TolIF2 gives dihalophosphoranes that are characterized by 31P NMR, however, with PhIOAc2, PhI(OTFA)2, or the cyclic chloro(benzoyloxy)iodane, no phosphoranes were observed. Reaction of these iodanes with PPh3 in the presence of primary, secondary, or tertiary alcohols results in either halogenation or acyl-transfer products in moderate to high yield.
References and Notes
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- 25 Sample Experimental Procedure Into a conical flask was added the 4-phenyl-2-butanol (0.063 g, 0.42 mmol, 1 equiv) and CH2Cl2 (0.5 mL), and to this was added PPh3 (1.1 equiv) and [bis(trifluoro-acetoxy)iodo]benzene (1.1 equiv). The reaction mixture was stirred at r.t. for 30 min, concentrated by rotary evaporation and subjected to column chromatography, where the stationary phase as acidified with 0.2% TFA in hexane. The crude reaction mixture was purified via column chromatography (10% EtOAc/hexane) to give 13c (0.066 g, 64% yield) as a colorless oil.19F NMR (282 MHz, CDCl3): δ = –75.58. 1H NMR (300 MHz, CDCl3): δ = 7.34–7.16 (m, 5 H), 5.11 (m, 1 H), 2.74–2.60 (m, 2 H), 2.15–1.87 (m, 2 H), 1.39 (d, J = 6.3 Hz, 3 H);13C NMR (75 MHz, CDCl3): δ = 157.1 (q, J = 41.5 Hz), 140.5, 128.6, 128.3, 126.3, 114.6 (q, J = 286.1 Hz), 75.8, 37.1, 31.4, 19.5.
For NMR studies on the synthesis of 2 with C2Cl6, see:
For syntheses of Ph3PF2 with various reagents such as XeF2, SF4, IF5, DAST, COF2, or HgF2, see: