A convenient synthesis of unsymmetric polyfluoroethers

A direct and rapid route to α,α-difluoroacylsilanes from trifluoroethanol

“…We used Falck's Mitsunobu conditions [21] (method D) to prepare small samples of 5f and though very satisfied with the yield, were very concerned about the potential to form multigramme quantities of the ether using this method. Toluene performed rather poorly when used to replace benzene (an heterogeneous mixture was formed at the concentration specified in the literature) as the reaction solvent, and the cost of the ADDP reagent was considerable.…”

“…Usual work-up and then distillation afforded ether 5k as a pale yellow oil (13.2 g, 71%); bp 135 8C; n max (film)/cm À1 : 3032w, 2938w, 1652m, 1435m, 1275s, 1154s, 968s; d H 3.12. Ether synthesis by Mitsunobu method D: preparation of 4-(2 0 ,2 0 ,2 0 -trifluoroethoxy)-1-(benzyloxy)-but-2Z-ene (5f) Tri-n-butylphosphine (1.5 mL, 6 mmol) was added to a solution of 4-benzyloxy but-2-en-1-ol (0.71 g, 4 mmol) and ADDP (1.5 g, 6 mmol) in dry benzene (60 mL) at room temperature [21]. After 10 min, trifluoroethanol (2.3 mL, 32 mmol) was added and the mixture was maintained at ambient temperature for 6 h. All volatiles were removed in vacuo and the mixture was purified by chromatography on silica gel (5% diethyl ether in light petroleum ether) to afford ether 5f (1.04 g, 100%, 98% by GC).…”

Polyfluoroalkylated tripyrazolylmethane ligands: Synthesis and complexes

“…We therefore turned our attention to Mitsunobu reaction as polyfluoroalkanols with short spacer between the hydroxy group and the perfluorinated group are sufficiently acidic to undergo ether formation providing more efficient protocol using ADDP 1,1 0 -(azodicarbonyl)dipiperidine in combination with tributylphosphane is employed [16]. Indeed, model reaction of octan-1-ol (4) with 1,1,1,3,3,3-hexafluoropropan-2-ol (5, HFIP) gave the target product 7, where a low yield of 28% was caused mainly by a small scale distillation.…”

Synthesis of novel lipophilic and/or fluorophilic ethers of perfluoro-tert-butyl alcohol, perfluoropinacol and hexafluoroacetone hydrate via a Mitsunobu reaction: Typical cases of ideal product separation

“…GC: 95%. 4.4.5.5.6.6.7.7.8.8.9.9.9-tridecafluorononane (5b) (21), 196 (11), 249 (100), 262 (6.9), 295 (9.6), 341 (19), 361 (14) 4.4.5.5.6.6.7.7.8.8.9.910.10.11.11.11-heptadecafluoroundecane (5c) Yield: 6.33 g (91%) colorless oil, bp: 224-227 8C, mp: À37 8C. GC: 99.8%.…”

“…F-tert-butyl alcohol and some fluorinated alcohols have been alkylated under Mitsunobu reaction to afford F-tert-butyl alkyl ethers [5,18] and R fn CH 2 OR type ethers [19], respectively. Fluorinated ethers shown above and those of highlighted in this study (Scheme 2) not only display unique physicochemical properties, but they are potential precursors for the synthesis of perfluorinated ethers with desired molecular weight range using fluorination methodologies reported by Chambers et al [20].…”