Palladium-Catalyzed Asymmetric Benzylation of Azlactones
作者:Barry M. Trost、Lara C. Czabaniuk
DOI:10.1002/chem.201302390
日期:2013.11.4
Asymmetric benzylation of prochiral azlactone nucleophiles enables the catalytic introduction of a benzyl group towards the synthesis of α,α‐disubstituted amino acids. Herein, we report an enantioselective palladium‐catalyzed process using chiral bis(diphenylphosphinobenzoyl)diamine (dppba) ligands. Naphthalene‐ and heterocycle‐based methyl carbonates react with a number of azlactones derived from
Catalytic Asymmetric Benzylation of Azomethine Ylides Enabled by Synergistic Lewis Acid/Palladium Catalysis
作者:Xin Chang、Jing-Di Ran、Xue-Tao Liu、Chun-Jiang Wang
DOI:10.1021/acs.orglett.2c00865
日期:2022.4.8
synergistic chiral Lewis acid/achiral Pd catalyst system was successfully applied in the enantioselective benzylation of various imine esters, giving a range of α-benzyl-substituted α-amino acid derivatives in satisfactory yield with excellent enantioselectivity. It is worth noting that this strategy exhibits good tolerance for bicyclic and monocyclic benzylic electrophiles. Furthermore, the utility of this
Preparation of new classes of aliphatic, allylic, and benzylic zinc and copper reagents by the insertion of zinc dust into organic halides, phosphates, and sulfonates
作者:Carole Jubert、Paul Knochel
DOI:10.1021/jo00046a026
日期:1992.9
The insertion of zinc dust into primary alkyl chlorides, bromides, phosphates, and sulfonates in a polar solvent (DMPU, DMA) and in the presence of a catalytic amount of LiI (0.2 equiv) provides new organozinc reagents of the type RZnX (X = Cl, Br, OSO2R, OP(O)(OR)2) in excellent yields. After the transmetalation to the corresponding copper reagent RCu(CN)ZnX using CuCN.2LiCl, the addition of electrophiles, such as Michael acceptors, affords the desired adducts. Similarly, various new allylic and benzylic zinc reagents were prepared without the formation of any Wurtz-coupling side product and reacted with various electrophiles.
CN114539206
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Benzylic Phosphates as Electrophiles in the Palladium-Catalyzed Asymmetric Benzylation of Azlactones
作者:Barry M. Trost、Lara C. Czabaniuk
DOI:10.1021/ja301461p
日期:2012.4.4
Palladium-catalyzedasymmetricbenzylation has been demonstrated with azlactones as prochiral nucleophiles in the presence of chiral bisphosphine ligands. Benzylic electrophiles are utilized under two sets of reaction conditions to construct a new tetrasubstituted stereocenter. Electron density of the phenyl ring dictates the reaction conditions, including the leaving group. The reported methodology