A dual reactivity of 2‐azetidinone‐tethered allenols may occur by judicious choice of the electrophilicreagents, 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.
Controlled Rearrangement of Lactam-Tethered Allenols with Brominating Reagents: A Combined Experimental and Theoretical Study on α- versus β-Keto Lactam Formation
作者:Benito Alcaide、Pedro Almendros、Amparo Luna、Sara Cembellín、Manuel Arnó、Luis R. Domingo
DOI:10.1002/chem.201101160
日期:2011.10.4
expansion of lactam‐tethered allenols to efficiently afford cyclic α‐ or β‐ketoamides with good yields and high chemo‐, regio‐, and diastereoselectivity, through controlled CC bondcleavage of the β‐ or γ‐lactamnucleus. Interestingly, in contrast to the rearrangement reactions of 2‐azetidinone‐tethered allenols, which lead to the corresponding tetramic acid derivatives (β‐keto lactam adducts) as the