The highly enantioselective Diels–Alderreaction of acetylenic dienophiles is shown to be effectively catalyzed by cationic chiral palladium complexes. Not only the degree but also the sense of enantioselectivity critically depends on the steric demand of ligands. Computational analyses indicate that the steric demand does not affect the endo/exo‐selectivity but the enantioface selectivity of dienes
One-Pot Multistep Bohlmann−Rahtz Heteroannulation Reactions: Synthesis of Dimethyl Sulfomycinamate
作者:Mark C. Bagley、Krishna Chapaneri、James W. Dale、Xin Xiong、Justin Bower
DOI:10.1021/jo048106q
日期:2005.2.1
The synthesis of dimethyl sulfomycinamate, the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl 2-oxo-4-(trimethylsilyl)but-3-ynoate is achieved in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol in 13 steps by the Bohlmann-Rahtz heteroannulation of a 1-(oxazol-4-yl)enamine or in 12 steps and 9% yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine and ammonia in ethanol.
Silver-catalyzed synthesis of disubstituted isoxazoles by cyclization of alkynyl oxime ethers
A facile and practical synthesis of 3,5-disubstituted isoxazoles via a silver-catalyzed cyclization and subsequent protonation of alkynyl oxime ethers has been developed. The methodology was successfully applied to the synthesis of a biologically active isoxazolecarboxylic acid. (C) 2011 Elsevier Ltd. All rights reserved.
Asymmetric Transfer Hydrogenation of α-Keto Amides; Highly Enantioselective Formation of Malic Acid Diamides and α-Hydroxyamides
作者:Shweta K. Gediya、Vijyesh K. Vyas、Guy J. Clarkson、Martin Wills
DOI:10.1021/acs.orglett.1c02830
日期:2021.10.15
The asymmetric transfer hydrogenation (ATH) of α-keto-1,4-diamides using a tethered Ru/TsDPEN catalyst was achieved in high ee. Studies on derivatives identified the structural elements which lead to the highest enantioselectivities in the products. The α-keto-amide reduction products have been converted to a range of synthetically valuable derivatives.
使用系留的 Ru/TsDPEN 催化剂在高 ee 下实现了 α-酮基-1,4-二酰胺的不对称转移氢化(ATH)。对衍生物的研究确定了导致产品中最高对映选择性的结构元素。α-酮酰胺还原产物已转化为一系列具有合成价值的衍生物。
Total Synthesis of Symbioramide: a Flexible Approach for the Efficient Preparation of Structural Isomers
concise, enantioselective total synthesis of symbioramide, starting from simple achiral compounds and racemic α-amino-β-keto esterderivatives is reported. This highly flexible strategy allowed the efficient preparation of seven structural isomers of the natural product as well. The synthesis relies on a convergent route that involves the efficient stereoselective reduction of a α-keto-β-yne ester, and