jo0607921_si_003.pdf (11.3 MB)
Strained Enamines as Versatile Intermediates for Stereocontrolled Construction of Nitrogen Heterocycles
journal contribution
posted on 2006-08-04, 00:00 authored by Gang Chen, Mikio Sasaki, Xinghan Li, Andrei K. YudinThis contribution assesses the synthetic utility of molecules that impose conformational constrains onto
aziridine-derived enamines. Synthetically versatile [3.1.0] and [4.1.0] bicyclic enamines have been prepared
by intramolecular oxidative cycloamination of aziridine-containing olefins. This process is initiated by
N-bromosuccinimide followed by base-mediated elimination of HBr to afford highly strained exo-bicyclic
enamines. In addition, intramolecular aziridine addition to aldehyde functionality was found to afford
the [3.1.0] and [4.1.0] bicyclic hemiaminals. These routes highlight possibilities for chemoselective
oxidative transformations of aziridine-containing precursors without nitrogen protection/deprotection steps.
The resulting products provide straightforward synthetic entries into a wide range of pyrrolidine- and
piperidine-containing heterocycles that are positioned toward subsequent transformations via aziridine
ring opening.