Capture of<i>In Situ</i>Generated Diazo Compounds or Copper Carbenoids by Triphenylphosphine: Selective Synthesis of<i>trans</i>- Alkenes and Unsymmetric Azines<i>via</i>Reaction of Aldehydes with Ketone-Derived<i>N</i>-Tosylhydrazones
作者:Qiang Sha、Yifei Ling、Wenyong Wang、Yunyang Wei
DOI:10.1002/adsc.201300302
日期:2013.8.12
AbstractCopper(II) acetylacetonate‐catalyzed Wittig olefination reactions of aldehydes with ketone‐derived N‐tosylhydrazones are reported. A series of tosylhydrazones was investigated and our results showed that the carbon number of the alkyl chain influences the E‐selecivity of the alkenes greatly. Alkenes could be obtained in moderate yields and excellent E‐selectivity when the carbon numbers were up to two. Under metal‐free conditions, triphenylphosphine was able to capture the in situ generated diazo compounds and the corresponding unsymmetrical azines were formed in good yields.magnified image
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
Bulky diadamantyl aryl phoshine ligands were synthesized and utilized in Buchwald‐Hartwig couplingreactions of sterically demanding ortho‐substituted arylchlorides. The ligands also showed enhanced catalytic activity in the coupling of tosyl hydrazones and aryl halides.