Facile synthesis of 3-substituted imidazo[1,2-<i>a</i>]pyridines through formimidamide chemistry
作者:Rasapalli Sivappa、Vamshikrishna Reddy Sammeta、Yanchang Huang、James A. Golen、Sergey N. Savinov
DOI:10.1039/c9ra05841a
日期:——
A facile entry to 3-aryl/alkenyl/alkynyl substituted imidazo[1,2-a]pyridines (3a–p, 6a–d & 9a–9e) has been developed from readily available benzyl/allyl/propargyl halides and 2-amino pyridines as substrates via formimidamide chemistry that is devoid of caustic or expensive reagents, such as transition metal complexes. Quantum chemical calculations performed to understand the underlying mechanism of
Dual ligand approach increases functional group tolerance in the Pd-catalysed C–H arylation of <i>N</i>-heterocyclic pharmaceuticals
作者:Igor Beckers、Aram Bugaev、Dirk De Vos
DOI:10.1039/d2sc04911b
日期:——
While C–Harylation enables the direct conversion of (hetero)aromatics without preinstalled functional or directing groups, its functional group tolerance should be increased to be viable in late-stage cross-couplings. In this work, we report on a dual ligand approach that combines a strongly coordinating phosphine ligand with a chelating 2-hydroxypyridine for the highly robust C–Hcoupling of bicyclic
catalytic amount of Fe(TPP)Cl and Zn dust. The reaction precludes the traditional, more favored click reaction between an organic azide and alkynes, and instead proceeds by an unprecedented metalloradicalactivation. The method is anticipated to advance access to the construction of important basic nitrogen heterocycles, which will in turn enable discoveries of new drug candidates.