Catalytic multicomponent cycloaddition assembling three different substances to form highly substituted bicyclo[4.2.0]octanes

A catalytic multicomponent (4+2)–(2+2) cascade cycloaddition process assembling three different substances has been developed. The process is able to rapidly provide a highly substituted bicyclo[4.2.0]octane skeleton from a 2-siloxydiene and two molecules of α,β-unsaturated carbonyl partners. The MCR process is accompanied by stereoselective formation of four carbon–carbon bonds and four stereogenic centers in a single operation.