Metal-catalyzed transformations has been established as a robust strategy in synthetic organic chemistry and related fields over the past decades, however, this area is dominated by late-transition metal catalysis. In contrast, rareearth metals, including scandium, yttrium, and the lanthanides (La–Lu), remain rarely explored. The unique electronic structures and chemical properties can make rare-earth metals either superior or complementary to the main group and late-transition metal catalysts for various chemical transformations. We have developed several half-sandwich rare-earth alkyl complexes as catalysts for challenging and unprecedented organic reactions with excellent regio-, diastereo- and enantio-control.1 For example, we have developed chiral binapthyl-derived Cp-ligated half-sandwich scandium catalysts and by fine tuning the steric environment around the catalyst-metal center, we have achieved the diastererodivergent asymmetric annulation of aldimines with styrenes. 2 We have also discovered that a tert-butyl substituent on the chiral Cp-ligand could enhance the noncovalent C–H···π interaction between the chiral ligand and the substrate to improve the enantioselectivity in asymmetric annulation of aldimines with internal alkynes.3These works represent the first examples of asymmetric [3+2] annulation of aldimines with simple alkenes and alkynes via C–H activation, providing a general access to biologically important chiral 1- aminoindane and 1-aminoindene derivatives.2-3 Very recently, we have successfully realized the first diastereo- and enantioselective intramolecular bis-cycloaddition of aldimines with tethered olefins via exo-selective C–H alkylation/nucleophilic addition cascade for the synthesis of a novel family of polycyclic chiral amines.4 This work is in sharp contrast with the late-transition metal-catalyzed methods where the nucleophilic addition is difficult to take place, producing monocyclic aldehydes or ketones as the final products from similar substrates. The synthetic and mechanistic details of these findings will be presented in the seminar. Apart from the asymmetric C–H annulation reactions, several selective and efficient synthetic transformations which are unique to rare-earth catalysts such as intramolecular C–H hydroarylation and hydrobenzylation with alkenes,5 isomerization of 1,1-disubstituted alkenes6 and hydrosilylation of internal alkynes7 will be described also.