Switchable Multicomponent Cyclization Reactions to Access Fluoroalkylated Dihydropyrimidines and Pyrimidines under Solvent‐Free Conditions
作者:Wanqing Zuo、Zhizhen Zhu、Yu Cheng、Lingling Zuo、Xiao Geng、Zhifang Li、Lei Wang
DOI:10.1002/cjoc.202300725
日期:2024.6.15
The development of switchable solvent-free multicomponent reactions to build high-value-added products is an important demand for organic synthesis. Herein, we detailed the successful implementation of a switchable strategy for the construction of diverse 4-fluoroalkyl-1,4-dihydropyrimidines and 4-fluoroalkyl-pyrimidines via a solvent/additive-free [3 + 2 + 1] annulation, starting from readily available
Synthesis of Ψ[CH(RF)NH]Gly-peptides: The dramatic effect of a single fluorine atom on the diastereocontrol of the key aza-Michael reaction
作者:Serena Bigotti、Stefano V. Meille、Alessandro Volonterio、Matteo Zanda
DOI:10.1016/j.jfluchem.2008.06.018
日期:2008.9
We describe in full-detail the synthesis of new Psi[CH(R-F)NH]-peptidomimetics, having different fluoroalkyl groups RF, as peptide bond surrogates. A key step in the synthesis is a stereoselective aza-Michael addition of chiral alpha-amino acid esters to beta-fluoroalkyl-alpha-nitroethenes. The diastereoselection of the process was influenced by the electronegativity, rather than by the steric bulk, of the fluorinated residue R-F in the beta-position of the nitroalkene acceptors. Replacement of a single F atom of R-F by a hydrogen or methyl group brings about a dramatic drop of stereocontrol, whereas Br, Cl and CF3, albeit bulkier than F, provide inferior results in terms of stereocontrol. A mechanistic hypothesis is provided. (c) 2008 Elsevier B.V. All rights reserved.
New functionalized, differently fluorinated building-blocks via Michael addition to γ-fluoro-α-nitroalkenes
The Michael addition of ketone-derived enamines, metalated methylene active compounds and N-methyl pyrroles to gamma-fluoro-alpha-nitroalkenes provided in moderate to good isolated yields the corresponding beta-fluoroalkyl nitro compounds, which represent new interesting, highly functionalized building blocks in organofluorine chemistry. (c) 2006 Elsevier B.V. All rights reserved.