Reactions of haloarenes, haloheteroarenes and dihalobenzenes with triphenylstannyl anions in DMSO and acetonitrile

Abstract

Abstract We studied different haloarenes, haloheteroarenes and dihalobenzenes with Ph3Sn− ions in DMSO or acetonitrile (CH3CN) as solvents, in the dark or under irradiation to determine whether the halogen metal exchange (HME) reaction or the SRN1 process prevails. With p-chloroanisole the photostimulated reaction is sluggish in DMSO. There is an HME reaction with 2- and 3-chlorothiophene. Bromoarenes (p-bromoanisole, p-dibromobenzene and 1-bromonaphthalene) and p-iodoanisole react with Ph3Sn− ions faster by an HME mechanism than by the SRN1 process. In the photostimulated reaction of 1-chloronaphthalene, 2-chloro and 3-chloropyridines with Ph3Sn− ions in DMSO, the substitution products are obtained in 72, 82 and 93% yields, respectively. With p-dichlorobenzene the di-substitution product is obtained in 90% yield. All these reactions occur by the SRN1 mechanism. Yields improve when the reactions are carried out in DMSO rather than in CH3CN.