Photostimulated Reactions of Potassium Diphenylarsenide with Haloarenes by the SRN1 Mechanism

Article abstract of DOI:10.1021/jo00325a013

Photostimulated reactions of haloarenes with potassium diphenylarsenide (3) were studied in liquid ammonia. p-Chloro-, p-bromo-, and p-iodotoluenes gave four products: triphenylarsine, p-tolyldiphenylarsine, di-p-tolylphenylarsine and tri-p-tolylarsine.Similarly, with p-chloro, p-bromo-, and p-iodoanisole as substrates, four arsines were found as products: triphenylarsine, p-anisyldiphenylarsine, di-p-anisylphenylarsine and tri-p-anisylarsine. p-Chlorotoluene and p-bromoanisole are unreactive in the dark, but with 4-chlorobenzophenone there is a dark reaction, which is accelerated by light and inhibited by m-dinitrobenzene and oxygen.Withthe latter substrate, only the straightforward substitution product is formed.These reactions are believed to occur by the S_RN1 mechanism, with an exstra feature of reversible coupling of aryl radicals with arside ions, which causes the scrambling of aryl rings.It is suggested that the low-lying ?^* MO of the benzophenone moiety prevents C-As bond breaking in the radical anion intermediate in that case.