Lewis Acid-Catalyzed Additions of (Benzotriazol-1-yl)diethoxymethane to Enol Ethers and Enamides. New Syntheses of beta-Alkoxyalkanal and beta-Aminoalkanal Acetals.

Addition of (benzotriazol-1-yl)diethoxymethane 11 to various acyclic and cyclic enol ethers and enamides produces the corresponding adducts, which were reacted with either NaAlH(4) or Grignard reagents to afford acyclic acetal-ethers (18a-f), cyclic alpha-(substituted)-beta-acetals (19a-c), amino-acetals (24a,b), and 1,3-amino-ethers (25), all known but previously difficult-to-access classes of compounds.