A Novel and Expeditious Approach to Symmetrical and Unsymmetrical 5,5-Spiroimide Building Blocks

Symmetrical and unsymmetrical spiro-bis-imides and corresponding 3-methoxycarbonyl succinimides were prepared in very good yields starting from dimethyl malonate and suitable α-bromoacetamides in a one-pot procedure or two-steps sequence, respectively. The mechanistic aspects of these transformations were also discussed.