Application of titanium catalysts for the syntheses of heterocycles

The metal catalyzed synthesis of heterocycles is becoming an important and highly rewarding protocol in organic synthesis. Traditional approaches require expensive or highly specialized equipment or would be of limited use to the synthetic organic chemist due to their highly inconvenient approaches. Titanium-mediated cyclization reactions have been recognized as some of the simplest and useful tools for regio- as well as stereoselective syntheses of five-membered N-heterocycles. This review summarizes the applications of titanium catalysts with emphasis of their synthetic applications for different heterocylces. This review covered interesting discoveries in the past few years.