Tandem in situ generation of azomethine ylides and base sensitive nitroethylene dipolarophiles

We have studied the behaviour of 2-acetoxy-nitroethane derivatives in the presence of triethylamine and of an azomethine ylide generated also by the action of this base in the same reaction mixture. Under these conditions the nitro-olefins are generated and react in situ with the corresponding dipoles, giving pyrrolidine derivatives in moderate to good yields. (C) 2000 Elsevier Science Ltd. All rights reserved.