Heterocycle Synthesis Based on Allylic Alcohol Transposition Using Traceless Trapping Groups


  • This work was supported by a grant from the National Science Foundation (CHE-1151979) and the University of Pittsburgh through a Mellon Fellowship to Y.X. We thank Dr. Bhaskar Godugu for conducting challenging mass spectrometric analyses.


Allylic alcohols undergo transposition reactions in the presence of Re2O7 whereby the equilibrium can be dictated by trapping one isomer with a pendent electrophile. Additional ionization can occur when the trapping group is an aldehyde or ketone, thus leading to cyclic oxocarbenium ion formation. Terminating the process through bimolecular nucleophilic addition into the intermediate provides a versatile method for the synthesis of diverse oxygen-containing heterocycles. Understanding the relative rates of the steps in the sequence leads to the design of reactions which create multiple stereocenters with good to excellent levels of control.