nonstereoselective course to provide a mixture of trans- and cis-substituted cycloadducts. This result can be explained by an isomerization of the intermediate azomethine ylide. Dimethyl 1,3-thiazolidine-2,2-dicarboxylates 14 and 15 were formed in the thermal reaction of dimethyl aziridine-2,2-dicarboxylate 11 with aromatic thioketones (Scheme3). On treatment of 14 and 15 with Raney-Ni in refluxing EtOH
Lewis Acid-Promoted Carbon−Carbon Bond Cleavage of Aziridines: Divergent Cycloaddition Pathways of the Derived Ylides
作者:Patrick D. Pohlhaus、Roy K. Bowman、Jeffrey S. Johnson
DOI:10.1021/ja0397963
日期:2004.3.3
Lewis acids are shown to cleave the carbon-carbon bond of activated aziridines at ambient temperature. The derived metal-coordinated azomethine ylides undergo cycloadditionreactions with electron-richalkenes. Cyclic alkenes afford products that are formally [4+2] adducts most likely derived from a Mannich-type addition to the ylide, followed by intramolecular Friedel-Crafts alkylation. Alternatively