[4 + 2] Cycloadditions of <i>N</i>-Alkenyl Iminium Ions: Structurally Complex Heterocycles from a Three-Component Diels−Alder Reaction Sequence
作者:Nihar Sarkar、Abhisek Banerjee、Scott G. Nelson
DOI:10.1021/ja8028153
日期:2008.7.1
N-Alkenyl iminium ions serve as conduits to three-component [4 + 2] cycloaddition reactions accessing structurally and stereochemically diverse piperidine derivatives. These cationic 2-azadienes participate in endo- or exo-selective [4 + 2] cycloadditions with electron-rich and neutral alkene dienophiles to generate a tetrahydropyridinium ion as the initial cycloadduct. In situ nucleophilic addition