This communication describes the utility of β‐amido allylboronate as a nucleophile in the catalytic amide allylation of N‐carbonyl imides. The reaction of the imide substrates with the boronates has been accomplished by using catalytic zinc bromide and basic additives (ethanol, potassium carbonate and 18‐crown 6‐ether), affording azaspiro‐γ‐lactones through a ring opening‐reclosure process with yields up to 100 %. The cost‐effective and easy‐to‐handle method established here tolerated for gram‐scale synthesis without significant loss of reaction efficiency.

A novel and facile synthesis of azaspiro-γ-lactones with a methylene-lactam framework from N-carbonyl imides is described. Mechanistic investigations provide evidence for a two-step reaction process involving ZnCl(2)-promoted addition of β-amido allylindium species followed by an unexpectedly molecular-sieves-mediated ring opening-reclosure concomitantly with the loss of an N-carbonyl unit.

The novel facile approach provides a new class of succinimide or phthalimide--derived azaspiro--lactones with an exo-methylene lactam ring as potential drug candidates. -(SENGOKU, T.; MURATA, Y.; ASO, Y.; KAWAKAMI, A.; INUZUKA, T.; SAKAMOTO, M.; TAKAHASHI, M.; YODA*, H.; Org. Lett. 17 (2015) 23, 5846-5849, http://dx.