Dimethylmalonyltrialkylphosphoranes: probing the steric effect on phosphorus and its stereochemical consequence in esterification reactions of chiral secondary alcohols
High chemical yields and high levels of stereochemical inversion are demonstrated in the phosphorane-mediated esterification reaction of chiral alcohols with non-hindered carboxylic acids through the incorporation of sterically non-hindered alkyl groups of phosphorus.
Substituent Effect on the Enantiomer-Differentiating Reaction of Lithiomethyl<i>p</i>-Tolyl Sulfoxide with Meta- or Para-Substituted (<i>R</i>)-(−)-Menthyl Benzoates
para-substituents, with 2 equivalents of racemic lithiomethyl p-tolyl sulfoxide displays the feature of an enantiomer-differentiating reaction, affording the corresponding optically active β-keto sulfoxides. The degree and the direction of enantioselectivity were affected by the nature of the substituent on benzene ring. The electron-releasing substituents trend to increase the %e.e. value. The reversal in the configuration
Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide‐Functionalized Phosphine Ligands
作者:Zhiyong Hu、Xiao‐Jing Wei、Jens Handelmann、Ann‐Katrin Seitz、Ilja Rodstein、Viktoria H. Gessner、Lukas J. Gooßen
DOI:10.1002/anie.202016048
日期:2021.3.15
organozinc reagents with aryl electrophiles using a cyclohexyl‐YPhos ligand bearing an ortho‐tolyl‐substituent in the backbone. This highly electron‐rich, bulky ligand enables the use of arylchlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively
A new robust methodology for gram-scale iron-catalyzed cross-coupling between alkyl Grignard reagents and alkenyl or aryl halides is developed. This method does not require toxic additives such as NMP or expensive ligands. Its efficiency relies on the use of simple alkoxide magnesium salts as additives. On the basis of these results, a new procedure for one-pot synthesis of substituted benzamides from
Modular Access to Chiral α-(Hetero)aryl Amines via Ni/Photoredox-Catalyzed Enantioselective Cross-Coupling
作者:Xiaomin Shu、De Zhong、Yanmei Lin、Xiao Qin、Haohua Huo
DOI:10.1021/jacs.2c02795
日期:2022.5.18
(hetero)aryl chlorides. These coupling reactions require no oxidants or organometallic reagents, feature feedstock starting materials, a broad substrate scope, and high enantioselectivities, and are applicable to late-stagediversification of medicinally relevant complex molecules. Mechanistic studies suggest that the nickel catalyst uncommonly plays multiple roles, accomplishing chlorine radical generation