82959-86-2Relevant 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.
WATER-INDUCED FORMATION OF AZOMETHINE YLIDE 1,3-DIPOLE. STEREOSPECIFIC AND REGIOSELECTIVE CYCLOADDITION REACTIONS
Tsuge, Otohiko,Kanemasa, Shuji,Hatada, Akira,Matsuda, Koyo
, p. 801 - 804 (2007/10/02)
An N-(trimethylsilylmethyl)imine generates the azomethine ylide 1,3-dipole of nonstabilized type, when treated with water, which cycloadds to olefinic dipolarophiles in a stereospecific and regioselective manner.
