Alcaide, Benito Almendros, Pedro Aragoncillo, Cristina Redondo, María C. Carbonyl Allenylation/Free Radical Cyclization Sequence as a New Regio- and Stereocontrolled Access to Bi- and Tricyclic β-Lactams A novel approach to racemic and enantiopure nonconventional fused bi- and tricyclic β-lactams has been developed by using regio- and stereocontrolled intramolecular free radical reactions in monocyclic 2-azetidinone-tethered allenynes and haloallenes. The access to allene cyclization precursors was achieved by metal-mediated carbonyl allenylation of appropriately substituted 4-oxoazetidine-2-carbaldehydes in an aqueous environment. The tin-promoted radical cyclizations of allene-β-lactams are totally regioselective for the central allenic carbon, providing bi- and tricyclic β-lactams containing a seven-membered ring. tricyclic;carbonyl;stereocontrolled intramolecular;Cyclization;haloallene;allenylation;Stereocontrolled Access;enantiopure nonconventional;allene cyclization precursors;regioselective;monocyclic;Bi;access;racemic;approach;New Regio;LactamsA;allenyne;lactam;Tricyclic;oxoazetidine;Sequence;Carbonyl;Radical;Allenylation;regio;allenic carbon 2007-03-02
    https://acs.figshare.com/articles/journal_contribution/Carbonyl_Allenylation_Free_Radical_Cyclization_Sequence_as_a_New_Regio_and_Stereocontrolled_Access_to_Bi_and_Tricyclic_Lactams/3020716
10.1021/jo061828s.s002