Reaction with carbonyl chloride fluoride

An alternative means of technical-scale access to fluoroarenes is the fluoroformate method. Starting from the corresponding phenol a fluoroformate is generated by reaction with carbonyl chloride fluoride and subsequently catalytically decarboxy-lated to the aryl fluoride, in the gas phase, by contact with hot platinum [80] (Scheme 2.30). A newer, greener variant of the fluoroformate process has recently been introduced by Rhodia. In this the fluoroformate is formed by the (catalyzed) reaction of the phenol with COj in HF, and the expensive platinum catalyst is replaced by an aluminum-based material. 

Although the most extensively recorded aspect of phosgene chemistry is its interaction with compounds at a nitrogen centre, only three reactions of carbonyl chloride fluoride with amines have been reported. No reports have appeared concerning the reactions of COCIF with tertiary amines, amino acids, hydrazine derivatives, imino compounds or nitrogen-containing heterocycles, to name but a few unstudied reagents. 

When sodium ethoxide is used in place of sodium hydroxide in the carbonylation reaction of benzyl halides with dicobalt octacarbonyl, ethyl esters are produced instead of the acids [15], Esters are also produced directly from iodoalkanes through their reaction with molybdenum hexacarbonyl in the presence of tetra-/i-butylammo-nium fluoride [16]. Di-iodoalkanes produce lactones [16]. The reaction can be made catalytic in the hexacarbonyl by the addition of methyl formate [16]. t-Butyl arylacetic esters are produced in moderate yield (40-60%) under phase-transfer catalytic conditions in the palladium promoted carbonylation reaction with benzyl chlorides [17]. 

In the reactions with carbonyl compounds9 and carboxylic acids,21 molybdenum(VI) fluoride is converted into molybdenum(VI) tetrafluoride oxide (MoOF4), and with the thiocarbonyl compounds24 into molybdenum(IV) sulfide, but with acid chlorides, its fate is not known. 

Carbonyl chloride fluoride is conveniently prepared from the reaction of the trichlorofluoromethane, CCI3F, with sulfur(IV) oxide ... 

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