Oxygen Activated, Palladium Nanoparticle Catalyzed, Ultrafast Cross-Coupling of Organolithium Reagents
作者:Dorus Heijnen、Filippo Tosi、Carlos Vila、Marc C. A. Stuart、Philip H. Elsinga、Wiktor Szymanski、Ben L. Feringa
DOI:10.1002/anie.201700417
日期:2017.3.13
The discovery of an ultrafast cross‐coupling of alkyl‐ and aryllithium reagents with a range of aryl bromides is presented. The essential role of molecular oxygen to form the active palladium catalyst was established; palladium nanoparticles that are highly active in cross‐coupling reactions with reaction times ranging from 5 s to 5 min are thus generated in situ. High selectivities were observed for
Murahashi Cross‐Coupling at −78 °C: A One‐Pot Procedure for Sequential C−C/C−C, C−C/C−N, and C−C/C−S Cross‐Coupling of Bromo‐Chloro‐Arenes
作者:Narayan Sinha、Dorus Heijnen、Ben L. Feringa、Michael G. Organ
DOI:10.1002/chem.201901678
日期:2019.7.11
The coupling of organolithium reagents, including strongly hindered examples, at cryogenic temperatures (as low as −78 °C) has been achieved with high‐reactivity Pd‐NHC catalysts. A temperature‐dependent chemoselectivity trigger has been developed for the selective coupling of arylbromides in the presence of chlorides. Building on this, a one‐pot, sequential coupling strategy is presented for the
preparation of 3-substitutedbenzo[b]thiophenes was developed. α-Substituted 2-(1-phenylethylthio)styrenes, which could easily be prepared from 2-mercaptophenyl ketones or benzenethiols in two or three steps, respectively, underwent 5-endo cyclization on treatment with iodine in the presence of sodium hydrogencarbonate in acetonitrile at room temperature to give 3-substitutedbenzo[b]thiophenes in fair to
A novel one-step synthesis of 3-substituted benzo[b]thiophene derivatives was achieved by dilithiation of (methylthio)benzene followed by reaction with varous aliphatic and aromatic carboxylic acid chlorides.
Abstract The radical reaction of benzenethiol with alkynes 1a-o carried out at 154 °C affords a mixture of thiol/alkyne adduct 3 and benzothiophene 5, deriving from vinyl radical intermediates 2 through hydrogen abstraction and 5-(π-endo)orthocyclization onto the adjacent thiophenyl ring, respectively. This latter reaction occurs through the reversible formation of cyclohexadienyl radical intermediates