New Syntheses and Chemistry of Hexafluorotropone

Abstract

Two new routes to hexafluorotropone have been developed, one from hexachlorotropone and a superior synthesis from hexafluorobenzene. Hexafluorotropone was found to be a very weak base, with a conjugate acid pK(a) of -6.2 +/- 0.5. The tropone adds in [6 + 4] fashion to cyclopentadiene and photocyclizes to hexafluorobicyclo[3.2.0]hepta-3,6-dien-2-one. Lithium hydroxide in benzene transforms the tropone into pentafluorotropolone, which functions as a bidentate ligand.

Theoretical studies on the protonation behavior of tropone and its metal complexes

“…Protonation of free tropones was found to take place at oxygen (1_OH + ) [5]. The protonated species (1_OH + ) has a pK a value of À1.02, indicating that tropones are much more basic than typical ketones [6].…”

4‐π‐Photocyclization: Scope and Synthetic Applications

“…[24] Bicycles 20 were obtained in low-moderate yields, although it should be noted that these reactions were carried out on a very small scale. Finally, perchlorinated [25] and perfluorinated [26] tropones have also been shown to undergo (reversible) 4-π-photocyclization upon irradiation, forming the corresponding [3.2.0]bicycles, although these reactions are unlikely to be of significant synthetic use.…”

“…Finally, perchlorinated and perfluorinated tropones have also been shown to undergo (reversible) 4‐π‐photocyclization upon irradiation, forming the corresponding [3.2.0]bicycles, although these reactions are unlikely to be of significant synthetic use.…”

Synthetic Applications of Lithium Hydroxide

“…Lithium hydroxide is a mild and efficient reagent used in several transformations in organic synthesis. It is used in tandem intramolecular aldol-aldol and sequential intramolecular Michael-aldol 1 reactions, as promoter of fragmentation reactions of optically active carbolactones providing g-hydroxycyclohexenones and g-butenolides, 2 in the synthesis of tropolones useful as bidentate ligands, 3 as promoter of glucosilation of 1-hydroxyindoles, 4 in the stereoselective Michael addition of thiols to N-methacryloylcamphorsultam followed by hydrolysis of the sulfonamides, 5 and it is applied in the deacylation of diazo-oxazolidones. 6,7 In addition, lithium hydroxide has been widely employed in Horner-Wadsworth-Emmons (HWE) reactions for preparation of a,b-unsaturated esters, a-unsaturated esters 8,9 and a,b-unsaturated nitriles.…”