82959-88-4Relevant articles and documents
One-Pot Reductive 1,3-Dipolar Cycloaddition of Secondary Amides: A Two-Step Transformation of Primary Amides
Huang, Pei-Qiang,Lang, Qi-Wei,Hu, Xiu-Ning
, p. 10227 - 10235 (2016/11/17)
The one-pot reductive 1,3-dipolar cycloaddition of secondary aromatic N-(trimethylsilylmethyl)amides with reactive dipolarophiles is reported. The method relies on the in situ generation of nonstabilized NH azomethine ylide dipoles via amide activation with triflic anhydride, partial reduction with 1,1,3,3-tetramethyldisiloxane (TMDS), and desilylation with cesium fluoride (CsF). Running under mild conditions, the reaction tolerated several sensitive functional groups and provided cycloadducts in 71-93% yields. The use of less reactive dipolarophile methyl acrylate led to the cycloadduct in only 40% yield. A (Z) geometric intermediate of NH-azomethine 1,3-dipole was postulated to account for the observed higher yields and higher cis diastereoselectivity for the substrates bearing an electron-withdrawing group. This model features an unconventional cyclic transition state via carbanion-aryl ring interaction. Because the starting secondary amides can be prepared from common primary amides, the current method also constitutes a two-step transformation of primary amides.
Synthesis of β-prolinols via [3+2] cycloaddition and one-pot programmed reduction: Valuable building blocks for polyheterocycles
Li, Jundong,Lin, Na,Yu, Lei,Zhang, Yandong
, p. 5777 - 5780 (2016/12/06)
A novel two-step synthesis of multisubstituted β-prolinols has been developed, featuring a [3+2] cycloaddition of azomethine ylides and a programmed reduction triggered by the combination of borane and lithium aluminum hydride (LAH). β-Prolinols are shown to be valuable building blocks for polyheterocycles.
Synthesis of cis-2-aryl-3-pyrrolidine carboxylic esters via diastereoselective cyclization of γ-imino esters using a TiCl 4/Et3N reagent system
Suresh, Surisetti,Periasamy, Mariappan
, p. 6291 - 6293 (2007/10/03)
Facile synthesis of cis-2-aryl-3-pyrrolidine carboxylates from readily accessible γ-imino esters by intramolecular cyclization mediated by a TiCl4/Et3N reagent system is described.