title: Iridium-catalyzed borylation of thiophenes: versatile, synthetic elaboration founded on selective C-H functionalization.
abstract: Iridium-catalyzed borylation has been applied to various substituted thiophenes to synthesize poly-functionalized thiophenes in good to excellent yields. Apart from common functionalities compatible with iridium-catalyzed borylations, additional functional group tolerance to acyl (COMe), and trimethylsilyl (TMS) groups was also observed. High regioselectivities were observed in borylation of 3-and 2,5-di-substituted thiophenes. Electrophilic aromatic C-H/C-Si bromination on thiophene boronate esters is shown to take place without breaking the C-B bond, and one-pot C-H borylation/Suzuki-Miyaura cross-coupling has been accomplished on 2- and 3-borylated thiophenes.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA.
authors.forename: Ghayoor A
authors.initials: GA
authors.lastname: Chotana
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA.
authors.forename: Venkata A
authors.initials: VA
authors.lastname: Kallepalli
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Maleczka
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA.
authors.forename: Milton R
authors.initials: MR
authors.lastname: Smith
keywords: Borylation; Bromination; Catalysis; C–H activation; Iridium; One-pot reactions; Suzuki-Miyaura cross-coupling; Thiophenes