Construction of novel bridged aromatic ring-fused oxazocine frameworks via an N-heterocyclic carbene-catalyzed azabenzoin reaction and radical-initiated cascade cyclization

A novel and efficient method for the construction of 1,5-methanobenzo[f][1,3]oxazocin-6-one compounds from o-vinyl benzaldehydes and N-acylarylimines has been developed. The synthesis proceeded through the sequential NHC-catalyzed azabenzoin reaction and radical-initiated regioselective intramolecular cascade cyclizations. This protocol features mild conditions, good functional group tolerance and high yields of products. Novel 6,10-methanopyrido[3,2-f][1,3]oxazocin-5-ones could also be synthesized from 2-vinylnicotinaldehyde and N-acylarylimines based on this method. Capitalizing on the operational simplicity and use of efficient C-C and C-X bond-forming reactions, this protocol combining NHC-catalyzed and radical-initiated reactions enables the assembly of bridged aromatic ring-fused oxazocine derivatives with versatile functional and structural diversities.

Automated summary

The study presents a novel and efficient method for constructing specific compounds with mild conditions, good functional group tolerance, and high yields. This method allows for the synthesis of versatile derivatives with bridged aromatic ring-fused oxazocine structures through the combination of NHC-catalyzed and radical-initiated reactions.