Synthesis of Tetrahydroindole Derivatives Using Titanium-Nitrogen Complexes Derived from Molecular Nitrogen

Synthesis of tetrahydroindole derivatives was realized from keto-alkyne using titanium-nitrogen complexes generated from Ti(OiPr)4, Li, and TMSCl. In this reaction, the electronwithdrawing group on the alkyne gave a good yield, and ketoalkynes having an aromatic ring on the alkyne also gave tetrahydroindole derivatives in good to moderate yields.