Organoindium mediated Csp3–S cross-coupling/migratory allenylation/thioannulation cascade: expedient synthesis of highly substituted thiophene frameworks
作者:Sushobhan Chowdhury、Tanmoy Chanda、Suvajit Koley、B. Janaki Ramulu、Raymond C.F. Jones、Maya Shankar Singh
DOI:10.1016/j.tet.2015.01.065
日期:2015.3
An operationally simple, efficient and convenient approach for the synthesis of highly substituted thiophene frameworks has been developed via the organoindium mediated coupling of alpha-enolic dithioesters and C2-C3 centres of propargylic bromides. The in situ generated propargyl indium species efficiently guides the unusual mode of fusion through an unprecedented Csp(3)-S cross-coupling/migratory C-allenylation/thioannulation cascade to furnish the corresponding thiophenes in a single synthetic operation. Furthermore, this protocol does not require any co-catalyst or activator. (C) 2015 Elsevier Ltd. All rights reserved.