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.