Reaction of the lithio-derivative of methoxyallene with hydrazones. Part 2: Formation of 3-pyrrolines and azetidines; synthetic and mechanistic aspects
作者:Valérie Breuil-Desvergnes、Jacques Goré
DOI:10.1016/s0040-4020(01)00031-x
日期:2001.3
3-pyrrolines when the time and temperature of the reaction are increased, but the rate of this transformation depends on the substituents of the terminal nitrogen. A reaction mechanism is proposed which involves intermolecular or intramolecular electron transfers from the lithium amide leading to hydrazinyl radicals. The relative stabilities of these intermediates may then explain the role of the substituents
作者:Enders, Dieter、Schubert, Heinrich、Nuebling, Christoph
DOI:——
日期:——
Efficient asymmetric synthesis of α-(heteroaryl)alkylamines by 1,2-addition of lithiated hetarenes to aldehyde-SAMP-hydrazones
作者:Dieter Enders、Giuseppe Del Signore
DOI:10.1016/j.tetasy.2003.12.036
日期:2004.3
An efficient enantio selective synthesis of alpha-(heteroaryl)alkylamines by nucleophilic 1,2-addition of lithiated hetarenes to aldehyde-SAMP-hydrazones followed by SmI2 or (BH3THF)-T-. N,N-single bond cleavage is described. The Cbz or benzoyl-protected amines are obtained in good overall yields (40-78%) and excellent enantiomeric excesses (ee = 88-99%). (C) 2004 Elsevier Ltd. All rights reserved.
Asymmetric Synthesis of Heterocyclic β-Aminosulfones via Nucleophilic 1,2-Addition of 2-Lithiobenzo[b]thiophene to Aldehyde-SAMP-hydrazones
作者:Dieter Enders、Giuseppe Del Signore
DOI:10.3987/com-04-s(p)3
日期:——
An efficient asymmetric synthesis of alpha-(1,1-dioxo-2,3-dihydro-1H-1lambda(6)-benzo[b]thiophen-2-yl)-substituted amines is described. Key steps of the synthesis are the nucleophilic 1,2-addition of 2-lithio-benzo[b]thiophene to aldehyde-SAMP-hydrazones, a benzo[b]thiophene oxidation using dimethyldioxirane and a highly diastereoselective conjugate reduction with L-Selectride(R). The heterocyclic beta-aminosulfones are obtained in five steps and good overall yields (23-49%) and very high diastereo-and enantiomeric excesses (de greater than or equal to 96%, ee = 88-99%).