| Autor: |
Patel SC; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Smith MW; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Mercer JAM; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Suzuki K; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Burns NZ; Department of Chemistry, Stanford University, Stanford, California 94305, United States. |
| Abstrakt: |
Cyclobutenes are highly useful synthetic intermediates as well as important motifs in bioactive small molecules. Herein, we report a regio-, chemo-, and enantioselective synthesis of cyclobutenes from olefins using N -sulfonyl-1,2,3-triazoles as vicinal dicarbene equivalents or alkyne [2 + 2] cycloaddition surrogates. Terminal and cis -olefins can be transformed into enantioenriched cyclopropanes via rhodium catalysis. Then, in one pot, treatment of these intermediates with tosyl hydrazide and base effects diazo formation followed by rhodium-catalyzed ring expansion to yield enantioenriched cyclobutenes. These cyclobutenes can be transformed into highly substituted, enantioenriched cyclobutanes, including structures relevant to natural product scaffolds. |
