Copper-/Silver-Mediated Arylation of C(sp2)–H Bonds with 2-Thiophenecarboxylic Acids
摘要:
A copper/silver-mediated arylation of (hetero)aryl C-H bonds with 2-thiophenecarboxylic acids has been achieved. The protocol features a broad substrate scope and high functional group tolerance. Preliminary mechanistic studies indicate that a cascade protodecarboxylation/dehydrogenative coupling process is likely involved.
Generation of 3- and 5-Lithiothiophene-2-carboxylates via Metal−Halogen Exchange and Their Addition Reactions to Chalcogenoxanthones
作者:Michael K. Gannon、Michael R. Detty
DOI:10.1021/jo062370x
日期:2007.3.1
Deprotonation and lithium−bromine exchange in 5- or 3-bromothiophene-2-carboxylic acids with t-BuLi form the corresponding dianion, which reacts highly regioselectively in the presence of 0.25 equiv of tetramethyl-1,2-ethylenediamine with 3,6-bis(dimethylamino) chalcogenoxanthones to give S- and Se-containing rhodamines. Quenching studies with D2O indicate that an extra equivalent of t-BuLi is not