Divergent Reactivity of 2‐Azetidinone‐Tethered Allenols with Electrophilic Reagents: Controlled Ring Expansion <i>versus</i> Spirocyclization

Abstract

Abstract A dual reactivity of 2‐azetidinone‐tethered allenols may occur by judicious choice of the electrophilic reagents, namely halogenating versus selenating reagents. Using common substrates, structurally different compounds, namely tetramic acids (from N ‐bromosuccinimide) or spirocyclic seleno‐β‐lactams (from N ‐phenylselenophthalimide), can be readily synthesized by these divergent protocols.