Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
作者:Eloi P Coutant、Vincent Hervin、Glwadys Gagnot、Candice Ford、Racha Baatallah、Yves L Janin
DOI:10.3762/bjoc.14.264
日期:——
We have explored here the scope of the age-old diethyl malonate-based accesses to α-aminoesters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered
An efficient hydrocyanation of α, β-unsaturated diesters with TMSCN catalyzed by MgI<sub>2</sub> etherate
作者:Haokun Pan、Hua Li、Huijun Liu、Xingxian Zhang
DOI:10.1080/10426507.2019.1700377
日期:2020.5.3
Abstract A mild, efficient and highly regioselective addition of trimethylsilyl cyanide (TMSCN) to α,β-unsaturated diesters has been achieved by using MgI2 etherate as catalystundersolvent-freeconditions. This protocol provides the corresponding β-cyano esters in high yields. Graphical Abstract
Ball‐Milling‐Enabled Reactivity of Manganese Metal**
作者:William I. Nicholson、Joseph L. Howard、Giuseppina Magri、Alex C. Seastram、Adam Khan、Robert R. A. Bolt、Louis C. Morrill、Emma Richards、Duncan L. Browne
DOI:10.1002/anie.202108752
日期:2021.10.18
conditions have led to the serendipitous discovery that manganese metal can mediate the reductive dimerization of arylidene malonates. The newly uncovered process has been optimized and its mechanism explored using CV measurements, radical trapping experiments, EPR spectroscopy, and solution control reactions. This unique reactivity can also be translated to solution whereupon pre-milling of the manganese
Catalytic enantioselective conjugate additions with easily accessible alkenylboronic acid pinacol esters as nucleophiles promoted by chiral copper complexes of N-heterocyclic carbenes are presented. These processes constitute an unprecedented instance of conjugate additions of a variety of functionalized alkenyl groups and afford desired products that are otherwise difficult to access in up to 98%
Enantiocontrolled Synthesis of β‐Branched α‐Amino Acids by Using Cu
<sup>I</sup>
‐Catalyzed 1,4‐Addition of Glycine Imines to β‐Substituted
<i>gem</i>
‐Diactivated Olefins
作者:Jorge Hernández‐Toribio、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1002/chem.201100374
日期:2011.5.27
Branching out! The catalytic asymmetric conjugate addition of glycinate Schiff bases to β‐substituted gem‐diactivated Michael acceptors under proton transfer conditions gives a variety of β‐branched α‐amino acids (see scheme; Dpm=diphenylmethylene, EWG=electron‐withdrawing group) with excellent levels of diastereo‐ (typically syn/anti >90:10) and enantiocontrol (90–99 % ee).
分支出!催化不对称共轭加成的甘氨酸Schiff碱至β -取代的宝石-diactivated质子转移条件下迈克尔受体给出的各种β-α支链氨基酸(参见方案; DPM =二苯基亚甲基,EWG =吸电子基团)具有优良的非对映体水平(通常是syn / anti > 90:10)和对映体控制(90–99% ee)。