Synfacts 2017; 13(01): 0071
DOI: 10.1055/s-0036-1589796
Metal-Mediated Synthesis
© Georg Thieme Verlag Stuttgart · New York

Ring-Forming Thioboration of C–C π-Bonds

Paul Knochel
Dorothee Ziegler
Faizi DJ, Davis AJ, Meany FB, Blum SA * University of California, Irvine, USA
Catalyst-Free Formal Thioboration to Synthesize Borylated Benzothiophenes and Dihydrothiophenes.

Angew. Chem. Int. Ed. 2016;
55: 14286-14290
Further Information

Publication History

Publication Date:
19 December 2016 (online)



Blum and co-workers developed a catalyst-free formal thioboration to produce borylated benzothiophenes and dihydrothiophenes in good to high yields.



The authors propose a reaction mechanism in which a boron-induced activation of the alkyne is followed by electrophilic cyclization to generate the borylated benzothiophene after demethylation of the sulfonium intermediate. Boron acts here as a carbophilic Lewis acid.