was found to be a highly efficient monodentate transient directing group (MonoTDG) for the palladium-catalyzed direct dehydrogenative cross-coupling of benzaldehydes with arenes. A diverse set of symmetrical and unsymmetrical 9-fluorenones was readily obtained in yields of 32-72% along with excellent regioselectivities and broad functional group compatibility as well as high atom economy under mild
Carbon−Hydrogen Bond Functionalization Approach for the Synthesis of Fluorenones and <i>ortho</i>-Arylated Benzonitriles
作者:Dmitry Shabashov、Jesús R. Molina Maldonado、Olafs Daugulis
DOI:10.1021/jo801300y
日期:2008.10.3
A sequence consisting of palladium-catalyzed benzamide ortho-arylation/reaction with (CF3CO)(2)O was developed allowing a convenient one-pot synthesis of ortho-arylated benzonitriles and fluorenone derivatives. The outcome of this transformation is dependent on the amide N-alkyl substituent. Dehydration of ortho-arylated N-cyclohexyl-benzamides by (CF3CO)(2)O results in efficient production of benzonitriles. In contrast, o-arylated N-propylbenzamides are converted to fluorenone derivatives.