Enantioselective reduction of <i>N</i>-alkyl ketimines with frustrated Lewis pair catalysis using chiral borenium ions
作者:Dan M. Mercea、Michael G. Howlett、Adam D. Piascik、Daniel J. Scott、Alan Steven、Andrew E. Ashley、Matthew J. Fuchter
DOI:10.1039/c9cc02900a
日期:——
Enantioselective reduction of ketimines was demonstrated using chiral N-heterocyclic carbene (NHC)-stabilised borenium ions in frustratedLewispair catalysis. High levels of enantioselectivity were achieved for substrates featuring secondary N-alkyl substituents. Comparative reactivity and mechanistic studies identify key determinants required to achieve useful enantioselectivity and represent a step
Noncovalent CH–π and π–π Interactions in Phosphoramidite Palladium(II) Complexes with Strong Conformational Preference
作者:Matej Žabka、Lavakumar Naviri、Ruth M. Gschwind
DOI:10.1002/anie.202106881
日期:2021.12
computational study of a supramolecular balance to quantify ligand–ligand interactions in metal complexes and induce high heterocomplex preferences. Noncovalent interaction areas of flexible chiral phosphoramidite ligands are identified in palladium complexes with high conformational stability. The combined CH–π and π–π interactions reveal design patterns for binding and folding of chiral ligands and catalysts
alkyl-containing lithium zincates, 1 : 1 mixtures of lithium and zinc amides were tested. Chiral (H-exo-born-R or H-endo-born-S) or/and achiral (lithium 2,2,6,6-tetramethylpiperidide or lithium diisopropylamide) secondaryamines gave good results, the best (81% yield and 44% ee in favor of the RP enantiomer) being obtained by using (endo-born-S)3ZnLi in THF at room temperature. Among other secondaryamines also
描述了使用混合锂-锌或锂-镉碱对二茂铁羧酸烷基酯 (FcCO 2 R) 进行对映选择性去金属化。以FcCO 2 Me为底物,由外-(α R )-或内-(α S ) -N- (α-苯乙基)冰片胺( H-外-本-R或H- )制备手性烷基氨基锌酸锂内生-S ) 进行了测试;最好的结果(27%产率和62%ee的赞成的[R P对映体)通过使用卜得到2(内切-born-S ) ZnLi 在四氢呋喃 (THF) 中在 -30 °C 下碘分解。由于 FcCO 2 Me 与含烷基的锌酸锂的相容性低,因此测试了氨基化锂和氨基化锌的 1:1 混合物。手性(H- exo- born- R或H- endo- born- S)或/和非手性(2,2,6,6-四甲基哌啶锂或二异丙基氨基锂)仲胺得到了很好的结果,最好的(81%的产率和44% ee 有利于R P对映异构体)是通过在室温下在 THF 中使用(内生S)3 ZnLi
Chiral Frustrated Lewis Pair@Metal‐Organic Framework as a New Platform for Heterogeneous Asymmetric Hydrogenation
作者:Yin Zhang、Songbo Chen、Abdullah M. Al‐Enizi、Ayman Nafady、Zhiyong Tang、Shengqian Ma
DOI:10.1002/anie.202213399
日期:2023.1.9
A highly active heterogeneouschiralfrustratedLewis pair system has been achieved for the first time via incorporating rationally designed bifunctional chiral FLP molecules into a MOF under the guidance of computational studies; the afforded CFLP@MOF demonstrated superb catalysis performances in heterogeneousasymmetrichydrogenation with excellent recyclability/regenerability.
Simplified Version of the Eschweiler–Clarke Reaction
作者:Klim O. Biriukov、Evgeniya Podyacheva、Ignatii Tarabrin、Oleg I. Afanasyev、Denis Chusov
DOI:10.1021/acs.joc.3c02476
日期:2024.3.1
The traditional Eschweiler–Clarke reaction is a three-component process involving formaldehyde, amine, and formic acid. In this work, we showed that the reductive potential of formaldehyde was sufficient to provide methylation of secondaryamines in the absence of acidic additives. Various acid-sensitive moieties remain intact under developed conditions. The scalability of the elaborated approach was