RESUMO
A selectivity-driven catalyst design approach was adopted to address chemoselectivity issues in the oxidative coupling of phenols. This approach was utilized for developing a Co(II)[salen]-catalyzed aerobic oxidative cross-coupling of phenols in a recyclable 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) solvent. The waste-free conditions offer a sustainable entry to nonsymmetric biphenols via a mechanistic scheme that involves coupling of a liberated phenoxyl radical with a ligated 2-naphthoxyl radical.
RESUMO
Direct entry to optically pure 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN) derivatives by an iron-catalyzed stereoselective oxidative cross-coupling reaction between 2-naphthol and 2-aminonaphthalene with a labile chiral auxiliary is reported. This efficient method offers entry to tailor-designed ( R a)- and ( S a)-NOBINs that are not accessible by any other means.
RESUMO
The copper(II) trifluoromethanesulfonate-catalyzed Pummerer reaction of ß-ketosulfoxides with 1,3-dicarbonyl compounds or π-nucleophiles such as phenols, arenes, and tetraallylsilane is reported. The mild conditions provide an efficient entry to a novel class of polysubstituted 3-alkylthiofuran and polysubstituted 3-thiobenzofuran heterocycles from readily available materials.