Phosphazene-catalyzed intramolecular cyclization of nitrogen-tethered alkynyl esters.
Intramolecular cyclization of nitrogen-tethered alkynyl esters catalyzed by phosphazene organosuperbases P2-tBu and P4-tBu was investigated. Both acyclic and cyclic substrates underwent 5-exo-dig and 5-endo-dig cyclization. This reaction is a rare example of the intramolecular addition of enolates of simple esters to alkynes.
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan. mterada@m.tohoku.ac.jp.
Azusa
A
Kondoh
Kenichi
K
Ando
Masahiro
M
Terada