Intermolecular reductive cross coupling of carbonyl compounds with nitriles induced by low-valent titanium

Samarium(II) Iodide-Promoted Intermolecular and Intramolecular Ketone-Nitrile Reductive Coupling Reactions

“…Reaction of acetophenone and benzonitrile with SmI 2 , gave ahydroxy ketones 3i, along with pinacol 4b (Entry 12). For comparison, when the same reaction was carried out using TiCl 4 /Zn as the reductant at reflux temperature, the cross coupling product ketone was obtained along with an olefin 22 while a-hydroxy ketone was not found.…”

Preparation of α-(2,2-Diphenylhydrazino)lactones and Related Compounds by Radical Cyclization: Use of Glyoxylic Acid Hydrazone Derivatives

“…t rans -2-Bromocyclohexyl [ N -(1,2,2-Triphenylethyl)-formimidoyl]formate (28). A solution of amine 27 (2.9326 g, 10.8 mmol) in CH 2 Cl 2 (10 mL) was added to a stirred solution of 26 (2.512 g, 10.8 mmol) in CH 2 Cl 2 (10 mL). The mixture was stirred overnight, and then evaporated.…”

Zinc and Trimethylsilyl Chloride Mediated Synthesis of 2,3,5-Trisubstituted Pyrrole Diesters from Nitriles and Ethyl Bromoacetate

“…16 Although there are a few reports on Zn-mediated conversion of nitriles into trisubstituted pyrroles by their reaction with 3-aryl nitroethylenes 17 or alkynes, 18 the reactions respectively require additional catalysts such as Pd(OAc) 2 or FeCl 3 for pyrrole formation. Liu's recent report on insertion of nitriles into zirconocene-1aza-1,3-diene complexes, and Chen's report on low-valenttitanium-mediated reductive condensation of nitriles with 1,3-diketones to furnish NH-pyrroles 19 are direct methods for conversion of nitriles into NH-pyrroles, but they both require elaborate and stringent reaction conditions. 20 We now report an efficient, straightforward, one-pot CN+3C protocol that provides regiodefined 2,3,5-trisubstituted pyrrole diesters such as 2a from one equivalent of nitrile such as 1a and three equivalents of ethyl bromoacetate.…”