Benzidine rearrangement reactions of polyether tethered cyclic N,N'-diaryl hydrazides.

N,N'-Diaryl hydrazides tethered with a polyether group at the meta positions undergo [5,5]-sigmatropic (benzidine) rearrangement reactions to furnish 4,4'-diamino-biphenyls (benzidines) strapped with a polyether unit at the 2,2'-positions.

Practical synthesis of azobenzenophanes.

We devised a practical synthetic route to azobenzenophanes via successive Cu- and Pd-catalyzed coupling reaction of aryl hydrazide and aryl halide followed by Cu(I)-mediated oxidation reaction.

Regioselective [5,5]-sigmatropic rearrangement reactions of aryl hydrazides.

[reaction: see text] N,N'-Aryl hydrazides with substituents at the ortho or meta positions undergo highly regioselective [5,5]-sigmatropic rearrangement reactions to furnish benzidines in good to excellent isolated yields. The presence of single substituent at either the ortho or meta position provides sufficient bias, effectively suppressing the formation of diphenylene, the major byproduct of the conventional benzidine rearrangement reaction.