Design and preparation of new palladium precatalysts for C-C and C-N cross-coupling reactions

Reaction Scheme

Abstract

Good to excellent yields�of aryl trifluoromethyl sulfides, which are an important class of compounds in both the pharmaceutical and agrochemical areas, can be achieved under mild conditions by the Pd-catalyzed reaction of aryl bromides with a trifluoromethylthiolate nucleophile (see scheme).

Substrates

Procedure

(COD)Pd(CH2TMS)2 (5.8 mg, 0.015 mmol, 1.5 mol%), BrettPhos (8.9 mg, 0.0165 mmol, 1.65 mol%) and 1 mmol of starting aryl bromide, if solid, were added to a flame dried 8 mL test tube with Teflon screw cap equipped with magnetic stir bar. The tube was sealed and evacuated and refilled with Ar (3x). After which 2 mL of dry toluene was added to the tube as well as aryl bromide if liquid. The solution was placed into a preheated 80?C oil bath for 60 s. The tube was removed from the oil bath generating solution A. AgSCF3 (280 mg, 1.3 mmol, 1.3 equiv) and (Ph)(Et)3NI (400 mg, 1.3 mmol, 1.3 equiv) were added to a flame dried 16 mL re-sealable screw cap tube equipped with two magnetic stir bars. The tube was evacuated and refilled with Ar (3x). Solution A was added via cannula. The tube containing solution A was then washed with 3 mL of toluene which was then cannulated over once more. The tube was placed into a preheated 80 �C oil bath with stirring for 2 h at which point the tube was removed and allowed to cool. The reaction mixture was then filtered through Si2O eluting with EtOAc. The solvent was removed under reduced pressure and the residue was purified via silica gel column chromotagraphy

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