73086-81-4Relevant academic research and scientific papers
Continuous-Flow Synthesis of Pyrylium Tetrafluoroborates: Application to Synthesis of Katritzky Salts and Photoinduced Cationic RAFT Polymerization
Sambiagio, Carlo,Ferrari, Matteo,Van Beurden, Koen,Ca', Nicola Della,Van Schijndel, Jack,Noel, Timothy
, p. 2042 - 2047 (2021/04/05)
Katritzky salts have emerged as effective alkyl radical sources upon metal- or photocatalysis. These are typically prepared from the corresponding triarylpyrylium ions, in turn an important class of photocatalysts for small molecules synthesis and photopolymerization. Here, a flow method for the rapid synthesis of both pyrylium and Katrizky salts in a telescoped fashion is reported. Moreover, several pyrylium salts were tested in the photoinduced RAFT polymerization of vinyl ethers under flow and batch conditions.
C-H Alkylation of Aldehydes by Merging TBADT Hydrogen Atom Transfer with Nickel Catalysis
Murugesan, Vetrivelan,Ganguly, Anirban,Karthika, Ardra,Rasappan, Ramesh
, p. 5389 - 5393 (2021/07/21)
Catalyst controlled site-selective C-H functionalization is a challenging but powerful tool in organic synthesis. Polarity-matched and sterically controlled hydrogen atom transfer (HAT) provides an excellent opportunity for site-selective functionalization. As such, the dual Ni/photoredox system was successfully employed to generate acyl radicals from aldehydes via selective formyl C-H activation and subsequently cross-coupled to generate ketones, a ubiquitous structural motif present in the vast majority of natural and bioactive molecules. However, only a handful of examples that are constrained to the use of aryl halides are developed. Given the wide availability of amines, we developed a cross-coupling reaction via C-N bond cleavage using the economic nickel and TBADT catalyst for the first time. A range of alkyl and aryl aldehydes were cross-coupled with benzylic and allylic pyridinium salts to afford ketones with a broad spectrum of functional group tolerance. High regioselectivity toward formyl C-H bonds even in the presence of α-methylene carbonyl or α-amino/oxy methylene was obtained.
Nickel-Catalyzed Cross-Coupling of Alkyl Carboxylic Acid Derivatives with Pyridinium Salts via C-N Bond Cleavage
Pulikottil, Feba Thomas,Pilli, Ramadevi,Suku, Rohith Valavil,Rasappan, Ramesh
, p. 2902 - 2907 (2020/04/09)
The electrophile-electrophile cross-coupling of carboxylic acid derivatives and alkylpyridinium salts via C-N bond cleavage is developed. The method is distinguished by its simplicity and steers us through a variety of functionalized ketones in good to excellent yields. Besides acid chlorides, carboxylic acids were also employed as acylating agents, which enabled us to incorporate acid-sensitive functional groups such as MOM, BOC, and acetal. Control experiments with TEMPO revealed a radical pathway.
Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts
No?l, Timothy,Sambiagio, Carlo,Sch?nbauer, David,Schnürch, Michael
, p. 809 - 817 (2020/05/18)
A ruthenium-catalyzed photoredox coupling of substituted N-aryltetrahydroisoquinolines (THIQs) and different bench-stable pyridinium salts was successfully developed to give fast access to 1-benzyl-THIQs. Furthermore, secondary alkyl and allyl groups were also successfully introduced via the same method. Additionally, the typically applied N-phenyl group in the THIQ substrate could be replaced by the cleavable p-methoxyphenyl (PMP) group and successful N-deprotection was demonstrated.
A concise preparation of η3-allylpalladium tetrafluoroborates from N-allylpyridinium tetrafluoroborates [1]
Malet, Ramon,Moreno-Manas, Marcial,Pleixats, Roser
, p. 25 - 30 (2007/10/03)
N-allyl-2,4,6-triphenylpyridinium tetratluoroborates react with bis(dibenzylideneacetone) palladium(0) and two equivalents of triphenylphosphine, or one equivalent of diphosphine, to give η3-allyl palladium tetrafluoroborates, 2,4,6-triphenylpyridine acting as neutral leaving group. Springer-Verlag Iberica 1996.
