RESUMO
A stereoselective and convenient route has been demonstrated to access (Z)-1,2-diazido alkenes from the corresponding 1,2-diboronic esters via a copper-mediated reaction with sodium azide. Alternately, mono-functionalization was regioselectively carried out with trimethylsilyl azide as an azidation reactant. The in situ conversion of bis-azides to the corresponding bis-triazoles can be readily achieved in the presence of copper sulfate and sodium ascorbate, while the modification of the catalytic system opened a new convenient route to bis-triazolo-pyrazines, a new class of fused heterocycles.
RESUMO
An efficient and straightforward synthesis of isoquinolines is reported from internal alkenyl boronic esters, easily prepared from the corresponding 1,2-bis(boronates), via a sequential copper-catalyzed azidation/aza-Wittig condensation. This synthetic method has been used to synthesize quinisocaine, a topical anesthetic used for the treatment of pain and pruritus, and further extended to thieno[2,3-c]pyridines by using 2-thiophenecarboxaldehyde as coupling partner in the first step.
RESUMO
An efficient and straightforward synthesis of 1-amino-1H-indenes is reported from 1,2-bis(boronates) via a sequential Suzuki-Miyaura coupling/Petasis cyclization reaction. Starting from the same monoboronic ester intermediates, an intermolecular version of this approach also afforded (Z)-α,ß-unsaturated amino esters in moderate to good yields.