Catalytic Syntheses of N-Heterocyclic Ynones and Ynediones by In Situ Activation of Carboxylic Acids with Oxalyl Chloride
作者:Christina Boersch、Eugen Merkul、Thomas J. J. Müller
DOI:10.1002/anie.201103296
日期:2011.10.24
bottleneck: α‐Keto carboxylicacids and N‐heterocyclic carboxylicacids are activated in situ with oxalylchloride then catalytically alkynylated to give ynediones and N‐heterocyclic ynones efficiently in a one‐pot fashion. 5‐Acylpyrazoles and 2‐phenylaminopyrimidines, potentially interesting for pharmaceutical applications, are readily synthesized in concise one‐pot, three‐component syntheses.
Diastereoselective allylation of α-ketoamides bearing camphor N-tosylpyrazolidinone auxiliary: efficient synthesis of highly optically active two stereoisomers
Complementary allylation conditions were developed for the synthesis of both diastereomers of tertiary homoallylic alcohols. Treatment of camphor N-tosylpyrazolidinone derived α-ketoamides with allyltributylstannane afforded both the individual homoallylic alcohols in high optical purity (up to 98% de) when the reaction was carried out in the presence of Sn(OTf)2 and PdCl2, respectively. The stereochemical
开发了互补的烯丙基化条件以合成叔均烯丙基醇的两种非对映异构体。当反应分别在Sn(OTf)2和PdCl 2的存在下进行时,用烯丙基三丁基锡烷处理樟脑N-甲苯磺酰基吡唑烷酮衍生的α-酮酰胺可提供高光学纯度(最高98%de)的两种均烯丙基醇。基于13 C NMR和FTIR研究,提出了反应中的立体化学结果和立体选择性的逆转。
Asymmetric Friedel–Crafts Alkylation of α-Substituted β-Nitroacrylates: Access to β<sup>2,2</sup>-Amino Acids Bearing Indolic All-Carbon Quaternary Stereocenters
A highlyenantioselectiveFriedel–Craftsalkylation reaction of indoles with acyclic α-substituted β-nitroacrylates is developed under the catalysis of Ni(ClO4)2–bisoxazoline complex at 1 mol % catalyst loading, affording chiral indolic β-nitroesters bearing all-carbon quaternary stereocenters in excellent yields and ees of up to 97%. Transformation of one of the products to β2,2-amino ester and t
Enantio- and chemoselective Brønsted-acid/Mg(<sup>n</sup>Bu)<sub>2</sub> catalysed reduction of α-keto esters with catecholborane
作者:Dieter Enders、Bianca A. Stöckel、Andreas Rembiak
DOI:10.1039/c4cc00427b
日期:——
The first enantio- and chemoselective Bronsted-acid catalysed reduction of alpha-keto esters with catecholborane has been developed. The alpha-hydroxy esters were obtained under mild reaction conditions in virtually quantitative yields and excellent enantioselectivities. With slight modifications both enantiomers can be obtained without any loss of selectivity.
3‐Hydroxypiperidine scaffolds were enantioselectively constructed in an atom‐economical way by sequentialaction of light and rhodiumupon N‐allylglyoxylamides. In a formal sense, the allylic CH bond was selectively cleaved and enantioselectively added across the ketonic carbonyl group with migration of the double bond (carbonyl‐ene‐type reaction).