Small Phosphine Ligands Enable Selective Oxidative Addition of Ar-O over Ar-Cl Bonds at Nickel(0)
Current methods for Suzuki-Miyaura couplings of nontriflate phenol derivatives are limited by their intolerance of halides including aryl chlorides. This is because Ni(0) and Pd(0) often undergo oxidative addition of organohalides at a similar or faster rate than most Ar-O bonds. DFT and stoichiometric oxidative addition studies demonstrate that small phosphines, in particular PMe3, are unique in promoting preferential reaction of Ni(0) with aryl tosylates and other C-O bonds in the presence of aryl chlorides. This selectivity was exploited in the first Ni-catalyzed C-O-selective Suzuki-Miyaura coupling of chlorinated phenol derivatives where the oxygen-containing leaving group is not a fluorinated sulfonate such as triflate. Computational studies suggest that the origin of divergent selectivity between PMe3 and other phosphines differs from prior examples of ligand-controlled chemodivergent cross-couplings. PMe3 effects selective reaction at tosylate due to both electronic and steric factors. A close interaction between nickel and a sulfonyl oxygen of tosylate during oxidative addition is critical to the observed selectivity.
Entz, Emily D.,Hooker, Leidy V.,Neufeldt, Sharon R.,Russell, John E. A.
supporting information
p. 15454 - 15463
(2020/10/18)
Iodine-induced synthesis of sulfonate esters from sodium sulfinates and phenols under mild conditions
An iodine-induced synthesis of sulfonate esters via cross-coupling reactions of sodium sulfinates with phenols is reported. This synthetic route is low-cost, facile, green and efficient, and could afford the target products with good to excellent yields u
Cs2CO3 catalyzed rapid and efficient conversion of amines into sulfonamides; Alcohols and phenols into sulfonic esters
A simple and efficient method has been developed for the sulfonylation of several amines, alcohols, and phenols by p-toluenesulphonylchloride (p-TsCl) in the presence of catalytic amount of Cs2CO3 at 25C to obtain sulfonamides and sulfonic esters in very good yields. Cs2CO3 has been found to be highly efficient catalyst. Taylor & Francis Group, LLC.
Reddy, M. B. Madhusudana,Pasha
experimental part
p. 1867 - 1875
(2011/10/11)
Graphite/methanesulfonic acid (GMA) as a new reagent for sulfonylation of phenols and thia-Fries rearrangement of aryl sulfonates to sulfonylphenols
A new facile method for direct sulfonylation of phenols was developed. Graphite in methanesulfonic acid (GMA) was used to prepare sulfonylphenols by sulfonylation of phenol and naphthalene derivatives with p-toluenesulfonic acid (=4-methylbenzenesulfonic acid) (Table 1) and the thia-Fries rearrangement of aryl sulfonates (Table 4). Mechanistic studies showed that the sulfonylation reaction of phenols in GMA occurred through an initial sulfonate formation followed by a thia-Fries rearrangement of the aryl sulfonate by an intermolecular mechanism (Scheme 3).