ChemInform Abstract: A New Prenylation Method Using the Lithium Enolate of Prenal. Reaction with Polyunsaturated Aldehydes. A Short Access to Retinal

The enolate of prenal 1 prepared from the corresponding silyl enol ether 2 or enol acetate 3 led to a γ-regiospecific reaction with polyunsaturated aldehydes 4 yielding dihydropyrans 5 leading after hydrolysis to polyenals 7 . This process allows the introduction of the isoprenyl skeleton. A synthesis of retinal. from β-ionylidenacetaldehyde is reported.