The B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Tandem Meinwald Rearrangement–Reductive Amination
作者:Martine R. Tiddens、Robertus J. M. Klein Gebbink、Matthias Otte
DOI:10.1021/acs.orglett.6b01744
日期:2016.8.5
A system of three coupledcatalytic cycles enabling the one-pot transformation of epoxides to amines via Meinwald rearrangement, imine condensation, and iminereduction is described. This assisted tandem catalysis is catalyzed by B(C6F5)3 resulting in the first tandem Meinwald rearrangement–reductive amination protocol. The reaction proceeds in nondried solvents and yields β-functionalized amines.
描述了三个耦合的催化循环的系统,该系统能够通过Meinwald重排,亚胺缩合和亚胺还原将环氧化物一锅转化为胺。这种辅助的串联催化由B(C 6 F 5)3催化,从而产生了第一个串联的Meinwald重排-还原胺化方案。该反应在未干燥的溶剂中进行,并产生β-官能化的胺。特别地,以高收率获得β-二芳基胺。
Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
作者:Robert J. Mayer、Nathalie Hampel、Armin R. Ofial
DOI:10.1002/chem.202003916
日期:2021.2.24
borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron‐centered Lewisacids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with
基于三芳基硼烷与各种以 O、N、S 和 P 为中心的路易斯碱在二氯甲烷中反应的 90 个实验平衡常数,开发了针对以硼为中心的路易斯酸的定量路易斯酸度/碱度标度。 20℃。使用线性自由能关系 log K B = LA B + LB B进行分析,可以通过两个描述符(一个用于路易斯酸度 ( LA B ))的总和来计算任何类型的硼烷/路易斯碱组合的平衡常数K B。一个用于路易斯碱度(LB B)。所得的路易斯酸度/碱度标度与固定的参考酸/碱无关,并且对于各种类型的三价硼中心路易斯酸有效。事实证明,新开发的路易斯酸度/碱度标度可以通过与量子化学计算或常见的物理有机描述符和已知热力学数据(Δ H )的线性关系轻松扩展。此外,该实验平台可用于硼烷催化反应的合理发展。
Iridium(I) Complexes with Anionic N-Heterocyclic Carbene Ligands as Catalysts for the Hydrogenation of Alkenes in Nonpolar Media
作者:Eugene L. Kolychev、Sabrina Kronig、Kai Brandhorst、Matthias Freytag、Peter G. Jones、Matthias Tamm
DOI:10.1021/ja406529c
日期:2013.8.21
complexes of anionic N-heterocycliccarbenes that contain a weakly coordinating borate moiety (WCA-NHC) was prepared in one step from free N-heterocycliccarbenes by deprotonation with n-butyl lithium followed by borane addition. The reaction of the resulting lithium-carbene adducts with [M(COD)Cl]2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) afforded zwitterionic rhodium(I) and iridium(I) complexes of the
Deoxygenative α-alkylation and α-arylation of 1,2-dicarbonyls
作者:Shengfei Jin、Hang T. Dang、Graham C. Haug、Viet D. Nguyen、Hadi D. Arman、Oleg V. Larionov
DOI:10.1039/d0sc03118f
日期:——
challenging but synthetically indispensable approach to α-branched carbonyl motifs that are widely represented among drugs, natural products, and synthetic intermediates. Here, we describe a simple approach to generation of boron enolates in the absence of strong bases that allows for introduction of both α-alkyl and α-aryl groups in a reaction of readily accessible 1,2-dicarbonyls and organoboranes. Obviation
[reaction: see text] Exposure of monocarbonyl iodonium ylides, generated by the ester exchange of (Z)-(2-acetoxyvinyl)-lambda(3)-iodanes with EtOLi, to organoboranes results in a 1,2-shift of a carbon ligand from boron to the ylide carbons, which probably generates hitherto uncharacterized alpha-boryl ketones.