Chiral Aziridine Sulfide N(sp3),S-Ligands for Metal-Catalyzed Asymmetric Reactions

A series of new bidentate N,S-ligands—aziridines containing a para-substituted phenyl sulfide group—was synthesized and evaluated in the Pd-catalyzed Tsuji–Trost reaction and addition of diethylzinc and phenylethynylzinc to benzaldehyde. A high enantiomeric ratio for the addition reactions (up to 94.2:5.8) was obtained using the aziridine ligand bearing a p-nitro phenyl sulfide group. Collected results reveal a specific electronic effect that, by the presence of particular electron-donating or electron-withdrawing groups in the PhS- moiety, influences the σ-donor–metal binding and the enantioselectivity of the catalyzed reactions.

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Transition-metal-catalyzed reactions of carbon-heteroatom bond formation by substitution and addition processes

Pure and Applied Chemistry ◽

10.1351/pac200577122021 ◽

2005 ◽

Vol 77 (12) ◽

pp. 2021-2027 ◽

Cited By ~ 21

Author(s):

Irina P. Beletskaya

Keyword(s):

Transition Metal ◽

Triple Bond ◽

Bond Formation ◽

Cross Coupling ◽

Addition Reactions ◽

Coupling Reactions ◽

Cross Coupling Reactions ◽

Transition Metal Catalyzed ◽

Catalyzed Reactions ◽

Metal Catalyzed

Two types of transition-metal-catalyzed cross-coupling reactions, which both lead to the formation of carbon-heteroatom bonds, are considered: RX + E-H and E-X + RM. The potential of addition reactions of E-H or E-E to double or triple bond in C-E bond formation is also demonstrated.

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Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

Current Organic Chemistry ◽

10.2174/1385272824666200211114540 ◽

2020 ◽

Vol 24 (3) ◽

pp. 231-264 ◽

Cited By ~ 3

Author(s):

Kevin H. Shaughnessy

Keyword(s):

Transition Metal ◽

Cross Coupling ◽

Coupling Reactions ◽

Cross Coupling Reactions ◽

Aryl Bromides ◽

Wide Range ◽

Sterically Demanding ◽

Transition Metal Catalyzed ◽

Catalyzed Reactions ◽

Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

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Chemistry of Unsymmetrical C1-Substituted Oxabenzonorbornadienes

Current Organic Synthesis ◽

10.2174/1570179417666210105121115 ◽

2021 ◽

Vol 17 ◽

Author(s):

Austin Pounder ◽

Angel Ho ◽

Matthew Macleod ◽

William Tam

Keyword(s):

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Substituent Effects ◽

Face Selectivity ◽

Transition Metal Catalyzed ◽

Catalyzed Reactions ◽

Metal Catalyzed ◽

Synthetic Intermediate

: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate which can be readily activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain on the alkene. To date, the understanding of transition-metal catalyzed reactions of OBD itself has burgeoned; however, this has not been the case for unsymmetrical OBDs. Throughout the development of these reactions, the nature of C1-substituent has proven to have a profound effect on both the reactivity and selectivity of the outcome of the reaction. Upon substitution, different modes of reactivity arise, contributing to the possibility of multiple stereo-, regio-, and in extreme cases, constitutional isomers which can provide unique means of constructing a variety of synthetically useful cyclic frameworks. To maximize selectivity, an understanding of bridgehead substituent effects is crucial. To that end, this review outlines hitherto reported examples of bridgehead substituent effects on the chemistry of unsymmetrical C1-substituted OBDs.

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