Oxygenative Perfluoroalkylation of Olefinic Compounds Using Perfluoroalkyl Iodide in the Presence of Oxygen

Abstract

Reactions of perfluoroalkyl iodides with styrene and its derivatives were investigated under radical conditions in the presence of oxygen. The photochemical reaction of styrene with CF3(CF2)5I in the presence of tributyltin hydride or tris(trimethylsilyl)silane under an oxygen atmosphere afforded the corresponding perfluoroalkylated alcohols in moderate yields together with CF3(CF2)5H. However, the photochemical reactions of styrene and its derivatives with CF3(CF2)nI (n = 3, 5) in the presence of hexabutylditin under oxygen produced the perfluoroalkylated alcohols in good yields. Furthermore, the reactions of styrenes with CF3(CF2)nI (n = 3, 5, 9) and Na2S2O4 in the presence of a base under air formed the same alcohols in good yields. The alcohols were found to provide a novel type of α-fluoroalkylated styrenes by acidic dehydration. Perfluoroalkylated α,β-unsaturated ketones were synthesized by oxygenative perfluoroalkylations of α-chlorostyrene and its derivatives using CF3(CF2)nI (n = 3, 5) under radical reaction conditions. The ketones were found to be good synthetic building blocks for perfluoroalkylated heterocycles, such as pyrazoles, dihydrodiazepines, pyrimidines, and isoxazoles.

Synthese α‐chiraler Ketone und chiraler Alkane durch eine radikalisch/ionische Kreuzungsreaktion von Vinyl‐Bor‐At‐Komplexen

“…Das Keton 2h fiel in 40 %G esamtausbeute und mit hoher Enantiomerenreinheit an. [16] Die Umsetzung verschiedener Enantiomeren-angereicherter Vinyl-Bor-At-Komplexe mit Perfluoralkyliodiden unter Bestrahlung und nachfolgender Oxidation führte zu chiralen aperfluoralkylierten Ketonen, die während der säulenchromatographischen Aufreinigung einer HF-Eliminierung unterliegen und die entsprechenden Vinylfluoride 3 liefern (Schema 3 Um das Potenzial der neuen Sequenz zu dokumentieren, erweiterten wir das Verfahren um die Herstellung von chiralen tert-Alkyl-Strukturmotiven unter Verwendung einer Protodeborylierungsreaktion. 2j), und Ketone mit a-quartärem Kohlenstoffatom lassen sich ebenfalls herstellen, allerdings in niedrigerer Ausbeute (2k).…”

“…Diese Strukturmotive sind nützliche Bausteine zur Synthese von fluorierten heterocyclischen Verbindungen, wie Pyrazolen, Pyrimidinen und Isoxazolen. [16] Um das Potenzial der neuen Sequenz zu dokumentieren, erweiterten wir das Verfahren um die Herstellung von chiralen tert-Alkyl-Strukturmotiven unter Verwendung einer Protodeborylierungsreaktion. [17] Der enantioselektive Aufbau von tertiären Alkylzentren ohne benachbarte funktionelle Gruppe,d ie den stereoselektiven Aufbau steuert, ist anspruchsvoll.…”

Radical Addition-Initiated Domino Reactions of Conjugated Oxime Ethers

“…35) Free radical-mediated hydroxyalkylation reactions involving both carbon-carbon bond formation and oxygenation processes represent an attractive approach for the preparation of complex molecules. [36][37][38][39][40][41][42][43][44][45] With this in mind, we investigated the triethylborane-induced hydroxyalkylation reaction of conjugated imines in the context of our previous study on hydroxysulfenylation. In the hydroxysulfenylation reaction, the intermediate radical generated by the addition of the thiyl radical to the carbon-carbon double bond is stabilized by a homoconjugative interaction between the carbon-centered radical and the sulfur atom, and this stabilization process is critical to the success of the transformation.…”

Redox system for perfluoroalkylation of arenes and α-methylstyrene derivatives using titanium oxide as photocatalyst

“…The residue was subjected to column chromatography on silica gel with hexane as eluent. 4,5,5,6,6,7,7,8,8,9,9,tridecafluorononene (441 mg, 52% yield based on the consumed iodide, colorless oil) was obtained as a mixture of 1-nonene (4a [16]) and 2-nonene (4b [16]) in the ratio of 13/1 as determined by 19 F NMR. The mixture was again subjected to column chromatography on silica gel with hexane as eluent.…”