Gold-Catalyzed Oxidative Cycloadditions to Activate a Quinoline Framework
作者:Deepak B. Huple、Satish Ghorpade、Rai-Shung Liu
DOI:10.1002/chem.201302533
日期:2013.9.23
gold! Gold‐catalyzed reactions of 3,5‐ and 3,6‐dienynes with 8‐alkylquinoline oxides results in an oxidative cycloaddition with high stereospecificity (see scheme; EWG = electron‐withdrawing group); this process involves a catalytic activation of a quinoline framework. The reaction mechanism involves the intermediacy of α‐carbonyl pyridinium ylides (I) in a concerted [3+2]‐cycloaddition with a tethered
Oxidant-Dependent Chemoselectivity in the Gold-Catalyzed Oxidative Cyclizations of 3,4,6,6-Tetrasubstituted 3,5-Dien-1-ynes
作者:Hsiao-Hua Hung、Yi-Ching Liao、Rai-Shung Liu
DOI:10.1021/jo401161h
日期:2013.8.16
chemoselectivity in the gold-catalyzedoxidativecyclization of 3,5-dien-1-ynes was observed when 3,5-dichloropyridine N-oxide replaced 8-methylquinoline N-oxide as the oxidant; the resulting cyclopentadienyl aldehydes were obtained in good yields. The altered chemoselectivity is attributed to a prior enyne cyclization in the presence of 3,5-dichloropyridine N-oxides. The use of N-iminopyridium ylide