Abstract
AuCl 3 -catalyzed formal [4 + 2]-cycloadditions between substituted allenes and N-hydroxyanilines are described. This reaction sequence comprises initial isomerizations of allenes to butadienes under N 2 and subsequent oxidations of N-hydroxyanilines to nitrosoarenes under O 2 . CuCl 2 (5 mol %) was added in the second step to increase the oxidation efficiency. The reactions are compatible with various 1,1-di- and 1,1,3-trisubstituted allenes and N-hydroxyaniline derivatives. Our experimental data reveal that the roles of AuCl 3 are 3-fold, including catalytic oxidations of N-hydroxyaniline derivatives to nitrosoarenes, isomerizations of alkyl-substituted allenes to dienes, and final nitroso/butadiene [4 + 2] cycloadditions. © 2014 American Chemical Society.