Ene reaction of Diels–Alder adducts of levoglucosenone and 1,3-dienes with acetaldehyde

Abstract

Diels–Alder adducts of levoglucosenone with isoprene, butadiene and piperylene in the presence of AlCl3 smoothly react with acetaldehyde or benzaldehyde to give products of the ene reaction, the hydroxy group of the primary intermediates participating in the formation of semiketal moiety. The yields of the reaction products depend both on the Lewis acid used (AlCl , BF ·Et O, ZnBr , SnCl or EtAlCl2) and on the nature of the substrate.