- λz) (λz - λx) to yield acyclic conformational ligand constants λ and substituent parameters ϱ. It is demonstrated that the λ constants already reported for an analogous series of 10 compounds with R = Br are transferable to the Cl series with ϱCl = 0.63 ± 0.07. Crude first approximations are also reported for the normalised (according to ϱBr = 1) ligand constants λCh3, λOH, λOCH3 and λ1 and for the
报告了27种通式RCF 2 CXYZ的不对称乙烷的合成和环境温度19 F NMR数据,包括10个具有R = Cl的化合物的完整系列以及5个配体H,F,Cl,Br和C的所有组合。在先前提出的启发式数学模型的理论框架内,将双峰19 F化学位移差异拟合为手性函数X = ϱR(λx-λy)(λy-λz)(λz-λx),以产生无环构象配体常数λ和取代基参数ϱ。证明了已经报道的类似的10种R = Br的化合物系列的λ常数可以转移到ϱ Cl的Cl系列。= 0.63±0.07。粗第一近似值也报道了归一化(根据ρ溴= 1)配体常数λ章3,λ OH,λ OCH 3和λ 1和所述取代基参数λ ħ。有人认为,λ值因此在不对称乙烷的构象分析中发挥作用,这在概念上类似于单取代环己烷中的构象自由能。
Dneprovskii, A. S.; Eliseenkov, E. V., Journal of Organic Chemistry USSR (English Translation), 1987, vol. 23, # 4, p. 711 - 719
作者:Dneprovskii, A. S.、Eliseenkov, E. V.
DOI:——
日期:——
<i>gem</i>
-Difluorination of Alkenyl <i>N</i>
-methyliminodiacetyl Boronates: Synthesis of α- and β-Difluorinated Alkylborons
作者:Wen-Xin Lv、Qingjiang Li、Ji-Lin Li、Zhan Li、E Lin、Dong-Hang Tan、Yuan-Hong Cai、Wen-Xin Fan、Honggen Wang
DOI:10.1002/anie.201810204
日期:2018.12.10
chemical transformations. Reported herein is a migratory geminal difluorination of aryl‐substituted alkenylN‐methyliminodiacetyl (MIDA) boronates using commercially available Py⋅HF as the fluorine source and hyperiodine as the oxidant. The protocol offers facile access to α‐ and β‐difluorinated alkylboron compounds, both of which have previously been challenging to prepare. Mild reaction conditions, broad