The<i>N</i>-Alkylation of Sulfonamides with Alcohols in Water Catalyzed by the Water-Soluble Iridium Complex {Cp*Ir[6,6′-(OH)<sub>2</sub>bpy](H<sub>2</sub>O)}[OTf]<sub>2</sub>
作者:Panpan Qu、Chunlou Sun、Juan Ma、Feng Li
DOI:10.1002/adsc.201300711
日期:2014.2.10
AbstractThe water‐soluble iridium complex Cp*Ir[6,6′‐(OH)2bpy](H2O)}[OTf]2 (Cp*=η5‐pentamethylcyclopentadienyl, bpy=2,2′‐bipyridine) was found to be a general and highly efficient catalyst for the N‐alkylation of the poor nucleophilic sulfonamides with alcohols as alkylating agents in water. The presence of OH units in the bpy ligand is crucially important for the catalytic activity of the iridium complex. Mechanistic investigations revealed that the catalytically active species is a ligand‐metal bifunctional iridium complex bearing an N,N′‐chelated 2,2′‐bipyridinated ligand and an aqua ligand. Notably, the present catalytic system and the proposed mechanism provide a new horizon and scope for the development of “hydrogen autotransfer (or hydrogen‐borrowing) processes”.magnified image
Site-Selective Cross-Coupling of Remote Chlorides Enabled by Electrostatically Directed Palladium Catalysis
作者:William A. Golding、Robert Pearce-Higgins、Robert J. Phipps
DOI:10.1021/jacs.8b08686
日期:2018.10.24
Control of site-selectivity in chemical reactions that occur remote from existing functionality remains a major challenge in synthetic chemistry. We describe a strategy that enables three of the most commonly used cross-coupling processes to occur with high site-selectivity on dichloroarenes that bear acidic functional groups. We have achieved this by repurposing an established sulfonylated phosphine