Synthesis of (<i>Z</i>)-<i>N</i>-Alkenylazoles and Pyrroloisoquinolines from α-<i>N</i>-Azoleketones through Pd-Catalyzed Tosylhydrazone Cross-Couplings
作者:Lucía Florentino、Fernando Aznar、Carlos Valdés
DOI:10.1002/chem.201301057
日期:2013.8.5
Azoles reacting in tandem: The ortho‐stereodirecting effect is the key to the stereoselective synthesis of (Z)‐N‐alkenylazoles I through the tosylhydrazide‐mediated Pd‐catalyzed cross‐coupling reaction of α‐N‐azoleacetophenones with ortho‐substituted aryl halides and nonaflates (see scheme). Additionally, the preorganization of the alkene allowed for the development of an auto‐tandem reaction involving
are employed as electrophiles in the Pd-catalyzed cross-coupling with tosylhydrazones affording di-, tri-, and tetrasubstituted olefins. Fine tunning of the reaction conditions are required to accomplish the coupling successfully, including the addition of LiCl and the presence of small amounts of water. Under the optimized conditions, the reactions proceed with high yield and also high stereoselectivity