Herein, we report the synthesis of functionalized of bicyclo[1.1.0]butanes (BCBs) enabled by Sc(OTf) 3 catalyst through ring-opening of 1,3-disubstituted bicyclic butane and carbonyl compounds. Interestingly, substituted indoline-2,3-diones were found to be suitable substrates to react with bicyclobutanes under mild reaction conditions, where functionalized cyclobutene products with two consecutive centers successfully obtained in good to high yields (up to 82%).

Pd-catalyzed asymmetric allylic C−H functionalization has emerged as a powerful tool to access chiral, densely functionalized molecules from easily ac-cessible alkenes, enabling the increase of the step- or atom-economy by minimizing functional group manipulations for preparing allylating reagents. Due to the inadequacy of stereoselection strategies, the asymmetric allylic C-H functionalization is still in the early stage. In this essay, we will describe our journey to identification of asymmetric catalytic systems, mechanism of allylic C−H activation, control of stereo- and regioselectivity, and applica-tions in asymmetric synthesis.