Naphthalene-1,8-diylbis(diphenylmethylium) as an Organic Two-Electron Oxidant: Benzidine Synthesis via Oxidative Self-Coupling of <i>N,N</i>-Dialkylanilines
作者:Terunobu Saitoh、Suguru Yoshida、Junji Ichikawa
DOI:10.1021/jo060662s
日期:2006.8.1
Naphthalene-1,8-diylbis(diphenylmethylium) exhibits a unique electron-transfer reduction behavior due to the close proximity of the two triarylmethyl cations, which form a C-C bond while accepting two electrons, leading to 1,1,2,2-tetraphenylacenaphthene. The preparation of the dication was readily accomplished under anhydrous conditions starting from a cyclic bis(triarylmethyl) ether, derived from 1,8-dibromonaphthalene. The process proceeded via deoxygenation accompanying the formation of a disiloxane on treatment with a silylating agent (Me3SiClO4 or Me3SiOTf) in 1,1,1,3,3,3-hexafluoropropan-2-ol. The dication was successfully employed for oxidative coupling of N, N-dialkylanilines at the paraposition to afford the corresponding benzidines in good to excellent yield.