No electron-withdrawing or electron-releasing substituents are necessary for the substrates in the rhodium-catalyzed [4+2] cycloaddition reaction between a vinylallene and an ordinary alkyne under mild conditions [Eq. (1)]. The use of the strongly electron-accepting P[OCH(CF3 )2 ]3 ligand affords the optimal rhodium catalyst. cod = 1,5-cyclooctadiene.
Rapid Synthesis of Aryl Fluorides in Continuous Flow through the Balz–Schiemann Reaction
作者:Nathaniel H. Park、Timothy J. Senter、Stephen L. Buchwald
DOI:10.1002/anie.201606601
日期:2016.9.19
The Balz–Schiemann reaction remains a highly utilized means for preparing aryl fluorides from anilines. However, the limitations associated with handling aryl diazonium salts often hinder both the substrate scope and scalability of this reaction. To address this, a new continuous flow protocol was developed that eliminates the need to isolate the aryl diazonium salts. The new process has enabled the