Lewis acid-controlled reactions of zirconacyclopentadienes with isocyanates and isothiocyanates. One-pot three- or four-component synthesis of multiply substituted iminocyclopentadienes and butadiene-tethered 1,6-bisamides and electrophilic cyclization

摘要: Abstract Multiply substituted zirconacyclopentadienes including bicyclic and zirconaindenes reacted with isocyanates isothiocyanates in the presence of Lewis acids to afford iminocyclopentadienes conjugated 1,6-bisamides, depending on nature acids, isocyanates, used. Only BF3 could be obtained high isolated yields when were treated isocyanates. On contrary, not mediate reaction isothiocyanates. For reactions isothiocyanates, EtAlCl2 was found effective generate as products. Interestingly, however, for work very differently from BF3. Instead iminocyclopentadienes, 1,6-bisamides mono-amides products substituents The path controlled by acids. As a demonstration usefulness thus unsaturated bisamides, electrophilic cyclization using NBS, I2 carried out. Electrophilic multisubstituted 1,6-bisamide derivatives afforded cyclic iminoethers excellent perfect selectivity. one amide groups took part cyclization.