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.
Reagents for Storage and Regeneration of Nonstabilized Azomethine Ylides: Spiroanthraceneoxazolidines
作者:Evgeny M. Buev、Vladimir S. Moshkin、Vyacheslav Y. Sosnovskikh
DOI:10.1021/acs.orglett.6b00475
日期:2016.4.15
Nonstabilized azomethineylides are easily trapped by anthraquinone to form stable spiro-oxazolidines, which have an unusual ability to undergo a cycloreversion in the presence of other dipolarophiles at 120–150 °C. All tested recycloadditions with carbonyl compounds and electron-poor alkenes occurred in moderate to high yields (41–92%). Moreover, increasing the reaction temperature to 210 °C made