摘要:
The combination of Cp2TiCl2 with 2 equiv of EtMgBr provides an effective reagent for the reductive cyclization of enynes, including ester-containing enynes, to bicyclic titanacyclopentenes. These metallacycles may then be transformed into bicyclic cyclopentenones or iminocyclopentenes in good yields by reaction with CO or an isocyanide, respectively.