Cascade and multicomponent reactions towards rapid synthesis of highly functionalized cyclobutanes

A large variety of organic substances having complicated polycyclic structures and a wide assortment of stereogenic centers are found in nature. These compounds often exhibit attractive and specific biological activities. Ideal strategies for preparing these structurally complex substances would involve sequences in which stereocontrolled formation of multiple carbon-carbon bonds occur in a single step starting with simple, readily available materials. Great attention has been given to the development of intermolecular cascade reactions and multi-component reactions owing to their high degree of atom economy and their applications in combinatorial chemistry as well as diversity-oriented syntheses. Herein we describe a new class of catalytic reaction of polycyclic structures including cyclobutane ring by utilizing cascade reaction and multi-component reaction, and its related catalytic reaction as well as their application to biologically active substances.