Tandem Alkylation-Reduction. Highly Stereoselective Synthesis of (E)-1-Hydroxymethyl Methyl Propenyl Ethers from Aldehydes Using 1-Lithio-1-methoxyallene

Article abstract of DOI:10.1021/jo00225a061

Tandem alkylation-reduction of a series of aldehydes, by alkylating with 1-lithio-1-methoxyallene followed by reducing with lithium-ammonia, regiospecifically and highly stereoselectively affords the 1-hydroxymethyl methyl propenyl ether in which the alkene geometry is exclusively E.Aldehydes that have been subjected to this convenient procedure include aromatic, aliphatic, and heterocyclic aldehydes.Subsequent hydrolysis, in the aromatic and aliphatic cases, affords the corresponding α-hydroxy ethyl ketones.The stereochemistry of the propenyl ethers was established by 13C NMR spectroscopy.A mechanism for the selective reduction of the methoxyallene system is proposed.