Browsing by Author "Russell, John E."
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Item Nickel-Catalyzed Stille Cross Coupling of C-O Electrophiles(2019-04) Russell, John E.; Entz, Emily D.; Joyce, Ian M.; Neufeldt, Sharon R.Aryl sulfamates, tosylates, and mesylates undergo efficient Ni-catalyzed cross coupling with diverse organostannanes in the presence of relatively unhindered alkylphosphine ligands and KF. The coupling is valuable for difficult bond constructions, such as aryl-heteroaryl, aryl-alkenyl, and aryl-alkynyl, using nontriflate phenol derivatives. A combination of experimental and computational studies implicates an unusual mechanism for transmetalation involving an 8-centered cyclic transition state. This reaction is inhibited by chloride sources due to slow transmetalation of organostannanes at a Ni(II)-chloride intermediate. These studies help to explain why prior efforts to achieve Ni-catalyzed Stille coupling of phenol derivatives were unsuccessful.