242484-65-7Relevant articles and documents
Catalyst-Free Decarboxylative Fluorination of Tertiary β-Keto Carboxylic Acids
Katada, Misaki,Kitahara, Kazumasa,Iwasa, Seiji,Shibatomi, Kazutaka
supporting information, p. 2408 - 2411 (2018/11/23)
Decarboxylative fluorination of tertiary β-keto carboxylic acids was performed using an electrophilic fluorinating reagent. The reaction proceeded in the absence of a catalyst or base to yield the corresponding α-fluoroketones with tertiary fluorocarbons in good to high yields. Considering that the α-fluorination of asymmetrical ketones often causes problems with the regioselectivity between the α- and α′-positions, this method could be a good alternative to the α-fluorination of simple ketones for the synthesis of tertiary fluoroketones.
Asymmetric fluorination of enamides: Access to α-fluoroimines using an anionic chiral phase-transfer catalyst
Phipps, Robert J.,Hiramatsu, Kenichi,Toste, F. Dean
, p. 8376 - 8379 (2012/06/30)
The use of a BINOL-derived phosphate as a chiral anionic phase-transfer catalyst in a nonpolar solvent allows the enantioselective fluorination of enamides using Selectfluor as the fluorinating reagent. We demonstrate that a wide range of stable and synthetically versatile α-(fluoro)benzoylimines can be readily accessed with high enantioselectivity. These compounds have the potential to be readily elaborated into a range of highly stereodefined β-fluoroamines, compounds that constitute highly valuable building blocks of particular importance in the synthesis of pharmaceuticals.
Intramolecular palladium-catalyzed alkane C-H arylation from aryl chlorides
Rousseaux, Sophie,Davi, Michael,Sofack-Kreutzer, Julien,Pierre, Cathleen,Kefalidis, Christos E.,Clot, Eric,Fagnou, Keith,Baudoin, Olivier
supporting information; experimental part, p. 10706 - 10716 (2010/09/17)
The first examples of efficient and general palladium-catalyzed intramolecular C(sp3)-H arylation of (hetero)aryl chlorides, giving rise to a variety of valuable cyclobutarenes, indanes, indolines, dihydrobenzofurans, and indanones, are described. The use of aryl and heteroaryl chlorides significantly improves the scope of C(sp3)-H arylation by facilitating the preparation of reaction substrates. Careful optimization studies have shown that the palladium ligand and the base/solvent combination are crucial to obtaining the desired class of product in high yields. Overall, three sets of reaction conditions employing PtBu3, PCyp3, or PCy3 as the palladium ligand and K 2CO3/DMF or Cs2CO3/pivalic acid/mesitylene as the base/solvent combination allowed five different classes of products to be accessed using this methodology. In total, more than 40 examples of C-H arylation have been performed successfully. When several types of C(sp3)-H bond were present in the substrate, the arylation was found to occur regioselectively at primary C-H bonds vs secondary or tertiary positions. In addition, in the presence of several primary C-H bonds, selectivity trends correlate with the size of the palladacyclic intermediate, with five-membered rings being favored over six- and seven-membered rings. Regio- and diastereoselectivity issues were studied computationally in the prototypal case of indane formation. DFT(B3PW91) calculations demonstrated that C-H activation is the rate-determining step and that the creation of a C-H agostic interaction, increasing the acidity of a geminal C-H bond, is a critical factor for the regiochemistry control.
