An intramolecular hetero Diels-Alder reaction of α-(alkynylsiloxy)aldimine derivatives

Intramolecular hetero Diels-Alder reactions of alpha-(alkynylsiloxy)aldimine derivatives were developed, alpha-(Alkynylsiloxy)aldehydes, which were prepared from 1,2-alkanediols in two steps, were converted into the corresponding biscarbamates or N-arylimines. In the presence of BF3. OEt2, the biscarbamates afforded oxazine derivatives in high diastereo selectivity. On the other hand, quinoline derivatives were obtained in good yields by treating the N-arylimines with trifluoromethanesulfonic acid. (C) 2000 Elsevier Science Ltd. All rights reserved.