Fluorine-Containing Reagents in Organic Synthesis

Abstract

RCH=CHR' or XZ-AgNO3 ^ (RCHXCHFR) -f RCHFCHFR' (X = Br or I) (60-95%)A simple variation of this procedure affords a-fluoro-(3-nitroalkanes: the alkene is added to a solution of nitronium tetrafluoroborate dissolved in pyridinium poly(hydrogen fluoride), a procedure which eliminates the problem of polymerization usually found in reactions conducted in anhydrous hydrogen fluoride [10], e.g. MeCH=CH2 + [NO21+[BF4]--in PPHF McCHFCH2NO2.Reactions with alcohols [9,11 ] Secondary and tertiary alcohols are readily converted to the corresponding fluorides oy pyridinium poly(hydrogen fluoride). With tertiary Across Conventional Lines Downloaded from www.worldscientific.com by PURDUE UNIVERSITY on 04/13/15. For personal use only.

The Synthesis and Glycoside Formation of Polyfluorinated Carbohydrates

“…95, 96 Olah's reagent (pyridinium poly(hydrogen fluoride), HF-py, also abbreviated as PPHF) is a mixture of 70% HF in pyridine (py), 97 equivalent to a 9:1 HF/py molar ratio, and is widely used in organic chemistry as a nucleophilic fluorinating agent. 94,98 Another HF-derived reagent is Et3N•3HF, triethyl amine trishydrofluoride (TREAT-HF). 99 While it has seen much use as fluorination agent through nucleophilic substitution reactions with activated alcohols and epoxides, as well as for halofluorination reactions, it has limited nucleophilicity.…”