Unsymmetrical Heterocycle Cross-Couplings Enabled by Sulfur(IV) Reagents

Abstract

Whereas metal-mediated cross-couplings find broad applications in syntheses of medicines, agrochemicals, and natural products, these powerful transformations have limited utility for Lewis basic substrates (e.g., heteroarenes), wherein basic functionalities coordinate to the metal center, hindering product formation. In this context, we have developed a transition-metal-free cross-coupling reaction mediated by sulfur(IV). This method leverages the ability of simple alkyl sulfinyl(IV) chlorides to form bipyramidal sulfurane complexes to drive a pseudo ‘reductive elimination’ process from the hypervalent sulfur atom, thereby readily providing unsymmetrical biheteroarenes.1 Introduction2 Historical Sulfurane(IV)-Mediated Couplings3 Unsymmetrical Heterocycle Cross-Couplings4 Conclusion