A metal-free tandem dehydrogenative α-arylation reaction of propargylic alcohols with 2-alkynylbenzaldoximes toward the synthesis of α-(4-bromo-isoquinolin-1-yl)-propenone skeletons
A tandemreaction of 2-alkynylbenzaldoximes with propargylic alcohols has been developed for the synthesis of α-(4-bromo-isoquinolin-1-yl)-propenones. Employing 2-alkynylbenzaldoximes as a precursor in the presence of Br2 generates 4-bromo-isoquinoline-N-oxides. Subsequently, dehydroxylation of propargylic alcohols gives carbocation intermediates, which are trapped using the N-oxides, affording aryl-substituted
Access to Functionalized Isoquinoline<i>N</i>-Oxides<i>via</i>Sequential Electrophilic Cyclization/Cross-Coupling Reactions
作者:Qiuping Ding、Jie Wu
DOI:10.1002/adsc.200800301
日期:2008.8.4
Electrophiliccyclization of 2-alkynylbenzaldoximes with various electrophiles leads to the formation of 4-iodoisoquinoline N-oxides or 4-bromoisoquinoline N-oxides under mild conditions. The reaction can be transferred to highly functionalized isoquinoline N-oxides via palladium-catalyzed cross-couplingreactions.