Chemistry of (Z)-2H-Heptafluorobut-2-ENE

Abstract

The research described within this thesis may be divided into four areas:1) The synthesis of (8) was investigated, and was shown to produce some novel by-products, including highly fluorinated dienes and even a triene. Perhaps most remarkable, was the presence of potassium pentakis(trifluoromethyl)cyclopentadienide in the reaction residue, since this constitutes a one step synthesis of this system from non- fluorinated precursors. The isolation of this salt proved challenging, but a variety of these salts have been isolated via the formation of 5H-pentakis(trifluoromethyl)cyclopentadiene, which is reported to be the strongest non- conjugated organic acid.2) The elimination of HF from (8) to give hexafluorobut-2-yne was explored, and several successful routes have been found. Equally interesting was the variety of products formed with bases. The 'non-nucleophilic' base DBU, was even shown to behave as a difunctional nucleophile with (8), resulting in a novel tricyclic pyrrole product, and the product structure was confirmed by a single X-ray crystallographic study.3) The use of (8) as a synthon for hexafluorobut-2-yne in Diels Alder reactions was investigated. This resulted in the discovery of a novel one pot route to a variety of bis(trifluoromethylated) furans.4) The reactions of (8) with a variety of nucleophiles was explored. The products obtained were identical to those that have been formed, or would be expected to be formed, from the reaction of the same nucleophile with hexafluorobutyne.