Synthesis of indazole-N-oxides via the 1,7-electrocyclization of azomethine ylides
作者:Miklós Nyerges、Andrea Virányi、Weimin Zhang、Paul W. Groundwater、Gábor Blaskó、László Tőke
DOI:10.1016/j.tet.2004.08.026
日期:2004.10
The first examples of the 1,7-electrocyclization of azomethine ylides onto a nitro group, to give benz-1,2,6-oxadiazepine intermediates are reported. Subsequent ring contraction results in the formation of indazole-N-oxides. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis of 5-Aryloxazolidines via 1,3-Dipolar Cycloaddition Reaction of a Non-Stabilized Azomethine Ylide with Aromatic Aldehydes
作者:John H. Ryan、Nadia Spiccia、Leon S.-M. Wong、Andrew B. Holmes
DOI:10.1071/ch07282
日期:——
The 1,3-dipolarcycloadditionreaction of a non-stabilized azomethine ylide 4a, formed in situ from N-(methoxymethyl)-N-(trimethylsilylmethyl)benzylamine 5 and a catalytic amount of trifluoroacetic acid, with aromatic aldehydes 3 gives rise to N-benzyl-5-aryloxazolidines 1. Under these conditions, 4-hydroxybenzaldehyde 3p undergoes two-fold addition of azomethine ylide 4a to afford bis adduct 11.