Asymmetric synthesis of β-fluoroaryl-β-amino acids
摘要:
The conjugate addition of lithium (R)-N-benzyl-N-(alpha-methylbenzyl)amide to a range of beta-fluoroaryl-alpha,beta-unsaturated esters gave the corresponding beta-amino esters with high diastereoselectivity and in good isolated yields. Sequential treatment of the resultant beta-fluoroaryl-beta-amino esters under optimised hydrogenolysis conditions, followed by ester hydrolysis with 2.0 M aq HCl, provided access to a range of beta-fluoroaryl-beta-amino acids in good yield. (c) 2012 Elsevier Ltd. All rights reserved.
Highly (<i>E</i>)-Selective Wadsworth−Emmons Reactions Promoted by Methylmagnesium Bromide
作者:Timothy D. W. Claridge、Stephen G. Davies、James A. Lee、Rebecca L. Nicholson、Paul M. Roberts、Angela J. Russell、Andrew D. Smith、Steven M. Toms
DOI:10.1021/ol802212e
日期:2008.12.4
An experimentally simple protocol for the very highly (E)-selective Wadsworth-Emmonsreaction [(E):(Z) selectivities in excess of 180:1 in some cases] of a range of straight-chain and branched aliphatic, substituted aromatic, and base-sensitive aldehydes via reaction with an alkyl diethylphosphonoacetate and MeMgBr is reported.
Non‐Chelate‐Assisted Palladium‐Catalyzed Aerobic Oxidative Heck Reaction of Fluorobenzenes and Other Arenes: When Does the C−H Activation Need Help?
作者:Francisco Villalba、Ana C. Albéniz
DOI:10.1002/adsc.202100677
日期:2021.10.19
sole oxidant and no redox mediator. Arenes with either electron-donating or electron-withdrawing groups can be functionalized in this way. Experimental data on the reaction with toluene as the model arene shows that the C−Hactivation step is turnover limiting and that the ligand structure is crucial to facilitate the reaction, which supports the involvement of the pyridone fragment in the C−H activation
An efficient, Pd(OAc)(2) catalyzed method for direct olefination of highly electron-deficient perfluoroarenes was developed. The reaction scope includes a series of activated and nonactivated alkenes in moderate to high yields with moderate to high regio- and stereoselectivities.
Asymmetric synthesis of β-fluoroaryl-β-amino acids
作者:Stephen G. Davies、Ai M. Fletcher、Linlu Lv、Paul M. Roberts、James E. Thomson
DOI:10.1016/j.tetasy.2012.07.001
日期:2012.6
The conjugate addition of lithium (R)-N-benzyl-N-(alpha-methylbenzyl)amide to a range of beta-fluoroaryl-alpha,beta-unsaturated esters gave the corresponding beta-amino esters with high diastereoselectivity and in good isolated yields. Sequential treatment of the resultant beta-fluoroaryl-beta-amino esters under optimised hydrogenolysis conditions, followed by ester hydrolysis with 2.0 M aq HCl, provided access to a range of beta-fluoroaryl-beta-amino acids in good yield. (c) 2012 Elsevier Ltd. All rights reserved.