Iodobenzene 3,4-dicyano

Abbreviations Ac acetyl Bn benzyl BSP 1-benzenesulfinyl piperidine BTIB bis(trifluoroacetoxy)iodobenzene DAST (diethylamino)sulfur trifluoride DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTSF dimethyl(methylthio)sulfonium tetrafluoroborate DMTST dimethyl(methylthio)sulfonium triflate DTBMP 2,6-Ai-tert-butyl-4-methylpyridine DTBP 2,6-di-tert-butylpyridine DTBPl 2,6-di-tert-butylpyridinium iodide FDCPT l-fluoro-2,6-dichloropyridinium triflate FTMPT l-fluoro-2,4,6-trimethylpyridinium triflate IDCP iodonium dicollidine perchlorate IDCT idonium dicollidine triflate LPTS 2,6-lutidinium p-toluenesulfonate LTMP lithium tetramethylpiperidide Me methyl MPBT S-(4-methoxyphenyl) benzenethiosulflnate NBS A-bromosuccinimide NIS A-iodosuccinimide NlSac A-iodosaccharin PPTS pyridinium p-toluenesulfonate TBPA tris(4-bromophenyl)ammoniumyl hexachloroantimonate Tf trifluoromethanesulfonyl TMTSB methyl-bis(methylthio)sulfonium hexachloroantimonate TMU tetramethylurea Tr trityl TTBP 2,4,6-tri-tert-butylpyrimidine. 

In addition, among the synthesis of sterically hindered and bifunctionalized structures, 1,8-dichloroanthracene (161) was lithiated to 162, which reacted with 3,4-dicyano-iodobenzene (163) to give the respective synthetic target, 1,8-diphenylanthracene (164) in 10% yield [74], Scheme 20. 

Nitrile imines can also be prepared conveniently by the oxidation of easily accessible hydrazones (Scheme 5.45). The oxidant generally used is chloramine-T (N-chloro-N-sodio-p-toluenesulfonamide, CAT). Other oxidants such as iodobenzene diacetate (IBD) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone have also been used. 

Yamamura comprebensively reviewed stoicbiometric oxidations of phenols with both metal (VjOg, VOClj, MnOj, CrOj, MoOCl, Tl O, Ag O) and nonmetal compounds (hypervalent iodobenzenes, 2,3-dichloro-5,6-dicyano-/)-benzoquinone, dioxirane, di-tert-butyl peroxide, di-ferf-butyl peroxyoxalate) [57]. Some of these reagents, for example, metal-free PhI(OAc)j and PhI(OCOCF3)j, seem to be rather safe and are especially useful in the low-scale synthesis of complex molecules of natural products. However, one should remember that none of the stoichiometric oxidations is compatible with the concept of green chemistry because such processes produce vast amounts of effluents, which are difficult to dispose of. For example, the active oxygen content in bis(trifluoroacetoxy)iodobenzene is only 3.8%, and a typical E-factor for oxidations with this oxidant lies in the range of 15-25. 

---