An efficient synthetic approach to polycyclic 2,5-dihydropyrroles from alpha-silyloxy ketones.
A three-step sequence to prepare polycyclic 2,5-dihydropyrroles from alpha-silyloxy ketones is presented. A Lewis acid-mediated ring fragmentation of cyclic gamma-silyloxy-beta-hydroxy-alpha-diazo esters provided tethered aldehyde ynoate intermediates which, when treated with amino acid silyl esters, underwent intramolecular azomethine ylide 1,3-dipolar cycloadditions. The 2,5-dihydropyrrole products were formed in good to excellent yield as single diastereomers.
Draghici
Cristian
C
Department of Chemistry, The University of Vermont, 82 University Place, Burlington, Vermont 05405, USA.
Huang
Qiufeng
Q
Brewer
Matthias
M
D003500:Cyclization; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D007659:Ketones; D011758:Pyrroles