Oxidative Cycloamination of Olefins with Aziridines as a Versatile Route to Saturated Nitrogen-Containing Heterocycles
摘要:
Highly reactive [5,3] and [6,3] bicyclic aziridines can be readily prepared from the corresponding NH aziridines and N-bromosuccinimide by intramolecular oxidative cycloamination of olefins. These compounds, including surprisingly stable exo-methylene bicyclic aziridines, provide versatile synthetic entries into a wide range of pyrrolidine- and piperidine-containing heterocycles.
Tandem anionic oxy‐Coperearrangement/radical oxygenation reactions provide δ,ϵ‐unsaturated α‐(aminoxy) carbonyl compounds, which serve as convenient precursors to diverse compound classes. Functionalized carbocycles are accessible by very rare all‐carbon 5‐endo‐trig cyclizations, but also common 5‐exo‐trig radical cyclizations, based on the persistent radical effect. The tandem reactions can be further
Persistent radical meets enolates: Catecholboron ketone enolates are oxidized efficiently under mild conditions by treatment with the persistent TEMPO radical. Catecholboron enolates are readily prepared by 1,4‐reduction of α,β‐unsaturated ketones or by transmetalation of silyl enol ethers and zinc enolates with chlorocatecholboranes. Enolate formation and oxidation can be performed as a one‐pot process
Strained Enamines as Versatile Intermediates for Stereocontrolled Construction of Nitrogen Heterocycles
作者:Gang Chen、Mikio Sasaki、Xinghan Li、Andrei K. Yudin
DOI:10.1021/jo0607921
日期:2006.8.1
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