Palladium-catalyzed α-regioselective allylic amination of Morita–Baylis–Hillman acetates with simple aromatic amines

Abstract

An efficient allylic amination of Morita-Baylis-Hillman acetates with simple aromatic amines provided good yields with excellent α-regioselectivity (up to exclusive α-product) under the catalysis of Pd(2)(dba)(3)/ferrocene-type diphosphine ligand.

Structural, Computational, and Spectroscopic Investigation of [Pd(κ3-1,1′-bis(di-tert-butylphosphino)ferrocenediyl)X]+(X = Cl, Br, I) Compounds

“…Of the [Pd­(P ∩ P)­Cl 2 ] (P ∩ P = dppf, dippf, dtbpf) catalysts, the dtbpf compound was found to be the least efficient in the cross-coupling of aryl Grignards with bromoanisoles . For the allylic amination of a Morita–Baylis–Hillman acetate the catalyst–ligand systems [Pd­(C 3 H 5 )­Cl] 2 –(P ∩ P) (P ∩ P = dppf, dippf, dtbpf) were similar in terms of product formation, but the dtbpf catalyst gave much higher regioselectivity of the product . Similarly, the reductive carbonylation of 4-bromoacetanilide using [Pd­(dppf)­Cl 2 ] as the catalyst gives predominantly the desired aryl aldehyde product, while using [Pd­(dtbpf)­Cl 2 ] gives exclusively the arene .…”

“…5 For the allylic amination of a Morita−Baylis−Hillman acetate the catalyst− ligand systems [Pd(C 3 H 5 )Cl] 2 −(P ∩ P) (P ∩ P = dppf, dippf, dtbpf) were similar in terms of product formation, but the dtbpf catalyst gave much higher regioselectivity of the product. 6 Similarly, the reductive carbonylation of 4-bromoacetanilide using [Pd(dppf)Cl 2 ] as the catalyst gives predominantly the desired aryl aldehyde product, while using [Pd(dtbpf)Cl 2 ] gives exclusively the arene. 7 For the [Ru(PPh 3 ) 3 (CO)(H 2 )]−(P ∩ P) (P ∩ P = dppf, dippf, dtbpf) catalyzed alkylation of tert-butyl ketonitrile with benzyl alcohol, the greater bulk of dtbpf significantly inhibits product formation.…”

Transition-Metal Complexes of Diphosphanes Containing the η7-Cycloheptatrienyl-η5-Cyclopentadienyl Titanium (Troticene) Sandwich Moiety

“…The resulting complexes are widely used for the preparation of bimetallic transition-metal complexes − and as ancillary ligands in homogeneous catalysis. − One of the most important derivatives of ferrocene is the commercially available 1,1′-bis­(diphenylphosphanyl)­ferrocene (dppf, A ; Figure ). ,, Its primary use as a ligand has been investigated in numerous homogeneous catalytic reactions, such as cross-coupling reactions (C–C, C–N, C–O, and C–S) in combination with palladium − or nickel, − and in electron-transfer catalysis. , Mechanistic studies revealed that the steric nature of the chelating ligands (especially the P–Pd–P bite angle) and also the electronic structure play a crucial role in the activity of the catalysts. − Interestingly, only a few studies have directly compared dppf with the more electron rich alkyl ligands B such as 1,1′-bis­(diisopropylphosphanyl)­ferrocene (dippf), 1,1′-bis­(dicyclohexylphosphanyl)­ferrocene (dcpf), and 1,1′-bis­(di- tert -butylphosphanyl)­ferrocene (dtbpf). − Variation of the PR 2 moiety in B leads to different steric and electronic properties, and these ligands have also found numerous applications in organometallic chemistry and homogeneous catalysis. − The most common coordination modes of 1,1′-bis­(phosphanyl)­ferrocene ligands are monodentate, chelating, and bridging . In addition, the ferrocene moiety is able to form complexes of type C with dative iron–metal (Fe–M) bonds, which are usually classified as weak donor–acceptor interactions, and this structural motif has been observed in complexes with sulfur, − phosphorus, ,−…”