Unusual Carbonyl Differentiation in the Lewis Acid-Catalyzed Allylation of Aldehydes with Tetraallyltin. Applications to Parallel Recognition and Shotgun Process

In contrast to conventional substrate selectivity in Lewis-acid promoted nucleophilic reactions wherein less electrophilic aldehydes react preferentially over the more electrophilic counterparts, addition of tetraallyltin to aldehydes occurs in a reversed sense. The substrate selectivity in Lewis acid-promoted nucleophilic addition is generally dependent on the combinations of substrates, nucleophiles, catalysts, etc. Such diversity leads to two one-pot protocols, parallel recognition and shotgun process wherein different chemical transformations take place directly on the separate reaction sites without recourse to protection–deprotection procedures. These two protocols are tunable by controlling the electronic properties of the substrates.