1448522-59-5Relevant articles and documents
Pd-catalyzed sp2 C-H hydroxylation with TFA/TFAA via weak coordinations
Rao, Yu
, p. 2472 - 2476 (2013)
An efficient sp2 C-H hydroxylation has been developed for the synthesis of a wide range of functionalized phenols with aryl ketones, benzoates, benzamides, acetanilides and sulfonamides through palladium(II) catalysis. A trifluoroacetic acid (TFA)/trifluoroacetic anhydride (TFAA) co-solvent system serves as the oxygen source and is the critical factor for weak coordination promoted C-H activation. Georg Thieme Verlag Stuttgart New York.
Pd-catalyzed C-H oxygenation with TFA/TFAA: Expedient access to oxygen-containing heterocycles and late-stage drug modification
Shan, Gang,Yang, Xinglin,Ma, Linlin,Rao, Yu
supporting information, p. 13070 - 13074 (2013/02/26)
Functionalized phenols are valuable industrial chemicals related to pharmaceuticals, agrochemicals, and polymers. Therefore, the direct catalytic hydroxylation of arenes to produce phenols has attracted much attention. Although tremendous progress has been made in this field, there are still difficult substrates which remain unmet challenges for direct hydroxylation in terms of regio- and chemoselectivity, as well as the practicality of current methods (Scheme 1). For example, 2-hydroxy aromatic ketones are useful synthetic intermediates for the preparation of various oxygen-containing heterocycles such as benzofuranone, chromanone, benzoxazole, and dibenzooxazepine; they also serve as key building blocks for drugs such as celiprolol, acebutolol, and propafenone. Traditional strategies for accessing 2-hydroxy aromatic ketones have mainly involved the oxidation of benzylic alcohols, the hydrolysis of aromatic halides, Fries rearrangement of esters or the demethylation of methyl phenyl ether. These methods generally suffer from one limitation or another, such as tedious reaction procedures, harsh reaction conditions, low yields, or the formation of side products. Hence, direct transformation of readily available aromatic ketones into valuable 2-hydroxylated products by transition metal-catalyzed C-H functionalization is arguably a highly efficient and atom-economic method to access these compounds. Moreover, developing a more general strategy for the regio- and chemoselective C-H oxygenation of a variety of challenging arenes would be especially desirable for phenol synthesis (Scheme 1).
