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
Chiral-Zn(NTf<sub>2</sub>)<sub>2</sub>-Complex-Catalyzed Diastereo- and Enantioselective Direct Conjugate Addition of Arylacetonitriles to Alkylidene Malonates
Chiral N,N′‐dioxide/Zn(NTf2)2 complexes were demonstrated to be highly effective in the direct asymmetricconjugateaddition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moderate‐to‐good yields with high diastereoselectivities (82:18–>99:1 d.r.) and enantioselectivities (81–99 % ee). The reactions
Malonate-type bis(oxazoline) ligands with sp2 hybridized bridge carbon: synthesis and application in Friedel–Crafts alkylation and allylic alkylation
作者:Hongliang Chen、Fengpei Du、Lei Liu、Jing Li、Qiuying Zhao、Bin Fu
DOI:10.1016/j.tet.2011.09.106
日期:2011.12
the Friedel–Crafts reaction and allylicalkylation. The Cu(II) complex of ligand 4b bearing the benzyl group afforded good to excellent enantioselectivity for the F–C adducts (up to >99% ee) between indole and alkylidene malonate, and the palladium complex of ligand 4c bearing the phenyl group afforded excellent enantioselectivity (up to 94% ee) for the allylicalkylation product.
A catalytic enantioselective conjugate addition with commercially available allenylboronic acid pinacol ester as nucleophile promoted by a chiral copper complex of N-heterocyclic carbene (NHC) is disclosed. This process constitutes an unprecedented instance of the conjugate addition that introduces an allenyl group into α,β-unsaturated carbonyl compounds, affording products that are otherwise difficult
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