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 Introduction
2 Historical Sulfurane(IV)-Mediated Couplings
3 Unsymmetrical Heterocycle Cross-Couplings
4 Conclusion
Key words
sulfur coupling - cross-coupling - sulfuranes - unsymmetrical biheteroarenes - Grignard
reagents