A straightforward method for the synthesis of highlyfunctionalizedvinylarenes through palladium‐catalyzed, norbornene‐mediated CHactivation/carbene migratory insertion is described. Extension to a one‐pot procedure is also developed. Furthermore, this method can also be used to generate polysubstituted bicyclic molecules. The reaction proceeds under mild conditions to give the products in satisfactory
Copper-Catalyzed Direct Benzylation or Allylation of 1,3-Azoles with <i>N</i>-Tosylhydrazones
作者:Xia Zhao、Guojiao Wu、Yan Zhang、Jianbo Wang
DOI:10.1021/ja111249p
日期:2011.3.16
Cu-catalyzed cross-coupling of N-tosylhydrazones with 1,3-azoles leads to the direct C-H benzylation or allylation. Cu carbene migratory insertion is proposed to play the key role in this transformation.
Pd-Catalyzed Highly Regio- and Stereoselective Formation of C–C Double Bonds: An Efficient Method for the Synthesis of Benzofuran-, Dihydrobenzofuran-, and Indoline-Containing Alkenes
A highly regio- and stereoselective C–C double bond formation reactionvia Pd-catalyzed Heck-type cascade process with N-tosylhydrazones has been developed. Various N-tosylhydrazones derived from both ketones and aldehydes are found to be efficient substrates to provide di- and trisubstitutedolefins with high regio- and stereoselectivity. Furthermore, this reaction has a good functional group tolerance
Directed C–C bond cleavage of a cyclopropane intermediate generated from<i>N</i>-tosylhydrazones and stable enaminones: expedient synthesis of functionalized 1,4-ketoaldehydes
-quaternary centers via regioseletive C-C bond activation has been described. Through cyclopropanation of bench-stable enaminones with in situ generated diazo reagents from N-tosylhydrazones, followed by selective C-C bond cleavage of the cyclopropane ring affords the 1, 4-ketoaldehyde derivatives in good to excellent yields. This method works with broad substrate scope and high regioseletivity.
A palladium-catalyzed heck-type cascadecyclization of (Z)-1-iodo-1,6-dienes with N-tosyl hydrazones is reported. The alkylpalladium intermediate coupled with the diazo compound, generating the second alkylpalladium species bearing two β-H, which generated a terminal alkene as the major products in the anti-Zaitsev way via the highly regioselective β-H elimination. It provided a new way to synthesize