Lewis Acid Catalyzed Alkylations of CC‐Multiple Bonds; Rules for Selective Enlargements of Carbon Skeletons

A preconception or many organic chemists, that cationic CC couplings are difficulty controllable and frequently lead to oligo- and polymeric products, would appear no longer to hold. If a difficultly ionizable product BX is formed from a readily ionizable educt AX in an electrophilic alkylation, then good yields can be achieved.