38282-01-8Relevant academic research and scientific papers
Functionalized hyperbranched grafts on polyethylene powder for support of Pd(0)-phosphine catalyst
Bergbreiter, David E.,Kippenberger, Andrew M.,Tao, Guoliang
, p. 2158 - 2159 (2002)
Hyperbranched grafts of poly(acrylic acid) have been modified with phosphine ligands for support of Pd(0) for use in allylic substitution chemistry.
Kinetics and mechanisms of the reactions of π-allylpalladium complexes with nucleophiles
Kuhn, Oliver,Mayr, Herbert
, p. 343 - 346 (1999)
Which nucleophiles are capable of attacking the allyl ligand of the Pd- stabilized allyl cation 1? This question is answered by the electrophilicity parameter of 1 which is derived from kinetic investigations.
Terminally functionalized polyisobutylene oligomers as soluble supports in catalysis
Bergbreiter, David E.,Li, Jun
, p. 42 - 43 (2004)
A new phase selective hydrocarbon soluble polymer support is described.
Enantioselective Allenoate-Claisen Rearrangement Using Chiral Phosphate Catalysts
Ellwart, Mario,Gensch, Tobias,Han, Seo-Jung,Lin, Hsin-Hui,Miró, Javier,Sigman, Matthew S.,Toste, F. Dean
, p. 6390 - 6399 (2020/04/27)
Herein we report the first highly enantioselective allenoate-Claisen rearrangement using doubly axially chiral phosphate sodium salts as catalysts. This synthetic method provides access to β-amino acid derivatives with vicinal stereocenters in up to 95percent ee. We also investigated the mechanism of enantioinduction by transition state (TS) computations with DFT as well as statistical modeling of the relationship between selectivity and the molecular features of both the catalyst and substrate. The mutual interactions of charge-separated regions in both the zwitterionic intermediate generated by reaction of an amine to the allenoate and the Na+-salt of the chiral phosphate leads to an orientation of the TS in the catalytic pocket that maximizes favorable noncovalent interactions. Crucial arene-arene interactions at the periphery of the catalyst lead to a differentiation of the TS diastereomers. These interactions were interrogated using DFT calculations and validated through statistical modeling of parameters describing noncovalent interactions.
C-N Bond Formation from Allylic Alcohols via Cooperative Nickel and Titanium Catalysis
Nazari, S. Hadi,Tiempos-Flores, Norma,Forson, Kelton G.,Bourdeau, Jefferson E.,Michaelis, David J.
, p. 10646 - 10654 (2018/09/06)
Amination of allylic alcohols is facilitated via cooperative catalysis. Catalytic Ti(O-i-Pr)4 is shown to dramatically increase the rate of nickel-catalyzed allylic amination, and mechanistic experiments confirm activation of the allylic alcohol by titanium. Aminations of primary and secondary allylic alcohols are demonstrated with a variety of amine nucleophiles. Diene-containing substrates also cyclize onto the nickel allyl intermediate prior to amination, generating carbocyclic amine products. This tandem process is only achieved under our cooperative catalytic system.
Borinic Acid Catalysed Reduction of Tertiary Amides with Hydrosilanes: A Mild and Chemoselective Synthesis of Amines
Chardon, Aurélien,Mohy El Dine, Tharwat,Legay, Rémi,De Paolis, Micha?l,Rouden, Jacques,Blanchet, Jér?me
, p. 2005 - 2009 (2017/02/19)
A reduction of various aryl, alkyl, and α,β-unsaturated amides with phenylsilane, catalysed by a borinic acid, is reported. The unprecedented reaction was carried out under very mild conditions and led to useful amines. Furthermore, the reaction tolerates a variety of functional groups. Initial investigations implicated that an intermediate diarylhydroborane is involved in the reaction mechanism.
Anti-Markovnikov rearrangement in sulfur mediated allylic C-H amination of olefins
Zhang, Zhong,Du, Hongguang,Xu, Jiaxi,Li, Pingfan
supporting information, p. 11547 - 11550 (2016/10/03)
Cationic rearrangement reactions usually follow Markovnikov's rule to give more substituted carbocations as stable intermediates. During our study on sulfur mediated allylic C-H amination of olefins, very rare cases of anti-Markovnikov rearrangement from secondary carbocations toward primary carbocations or primary triflates were observed.
N-heterocyclic carbene C,S palladium(II) π-allyl complexes: Synthesis, characterization, and catalytic application in allylic amination reactions
Krishnan, Deepa,Wu, Meiyi,Chiang, Minyi,Li, Yongxin,Leung, Pak-Hing,Pullarkat, Sumod A.
supporting information, p. 2389 - 2397 (2013/06/27)
A series of five-membered N-heterocyclic carbene C,S palladium(II) π-allyl complexes were successfully developed and characterized. Structural analyses of these complexes revealed that the organopalladium chelates adopt a skew-envelope conformation with a
η1-Allylpalladium complexes with a tridentate PNP ligand with different phosphino groups
Crociani, Bruno,Antonaroli, Simonetta,Paoli, Paola,Rossi, Patrizia
, p. 12490 - 12500 (2013/01/14)
The iminodiphosphine 2-(PPh2)C6H4-1- CHNC6H4-2-(PPh2) (P-N-P′) is used for the preparation of the complexes [Pd(η1-CHR1-CHCR 2R3)(P-N-P′)]BF4 [R1 = R 2 = R3 = H: (1); R1 = R2 = Ph, R3 = H: (2); R1 = R3 = H, R2 = Ph: (3); R1 = H, R2 = R3 = Me: (4)]. The P-N-P′ tridentate coordination and the η1-allyl bonding mode in the solid are confirmed by the X-ray structural analysis of 1. In solution, the complexes 1 and 2 undergo an η1-η3- η1 rearrangement at 298 K interconverting the bonding site of the allyl group. A five-coordinate structure with the phosphine ligands in the axial position is proposed for the η3-allyl intermediate. For the dynamic process, a ΔG≠ value of 53.8 kJ mol-1 is obtained from 1H NMR data of 2. In 3 and 4, the allyl ligand is rigidly bound to the metal through the less substituted terminus, in line with the higher free energy content of the corresponding isomers: [Pd(η1-CHPh-CHCH2)(P-N-P′)]+ +48.78 kJ mol-1; [Pd(η1-CMe2-CHCH 2)(P-N-P′)]+ +69.35 kJ mol-1. The complexes react with secondary amines in the presence of fumaronitrile at different rates yielding allylamines and the palladium(0) derivative [Pd(η2-fn)(P-N-P′)] (5). On the basis of charge distribution on the allylic carbon atoms and of steric factors, the difference in rate and the regioselectivity in the amination of 1-3 are better rationalized by a mechanism with nucleophilic attack at the η3-intermediate rather than by an SN2 mechanism with nucleophilic attack at the Pd-CHR1 carbon atom. The high regioselectivity in the reaction of 4 with piperidine implies an SN2′ mechanism with nucleophilic attack at the CMe2 allyl carbon. A dynamic process occurs also for the 18-electron complex 5 consisting in a dissociation-association equilibrium of the olefin.
η1-Allylpalladium complexes with a tridentate PNP ligand with different phosphino groups
Crociani, Bruno,Antonaroli, Simonetta,Paoli, Paola,Rossi, Patrizia
, p. 12490 - 12500,11 (2012/12/13)
The iminodiphosphine 2-(PPh2)C6H4-1- CHNC6H4-2-(PPh2) (P-N-P′) is used for the preparation of the complexes [Pd(η1-CHR1-CHCR 2R3)(P-N-P′)]BF4 [R1 = R 2 = R3 = H: (1); R1 = R2 = Ph, R3 = H: (2); R1 = R3 = H, R2 = Ph: (3); R1 = H, R2 = R3 = Me: (4)]. The P-N-P′ tridentate coordination and the η1-allyl bonding mode in the solid are confirmed by the X-ray structural analysis of 1. In solution, the complexes 1 and 2 undergo an η1-η3- η1 rearrangement at 298 K interconverting the bonding site of the allyl group. A five-coordinate structure with the phosphine ligands in the axial position is proposed for the η3-allyl intermediate. For the dynamic process, a ΔG≠ value of 53.8 kJ mol-1 is obtained from 1H NMR data of 2. In 3 and 4, the allyl ligand is rigidly bound to the metal through the less substituted terminus, in line with the higher free energy content of the corresponding isomers: [Pd(η1-CHPh-CHCH2)(P-N-P′)]+ +48.78 kJ mol-1; [Pd(η1-CMe2-CHCH 2)(P-N-P′)]+ +69.35 kJ mol-1. The complexes react with secondary amines in the presence of fumaronitrile at different rates yielding allylamines and the palladium(0) derivative [Pd(η2-fn)(P-N-P′)] (5). On the basis of charge distribution on the allylic carbon atoms and of steric factors, the difference in rate and the regioselectivity in the amination of 1-3 are better rationalized by a mechanism with nucleophilic attack at the η3-intermediate rather than by an SN2 mechanism with nucleophilic attack at the Pd-CHR1 carbon atom. The high regioselectivity in the reaction of 4 with piperidine implies an SN2′ mechanism with nucleophilic attack at the CMe2 allyl carbon. A dynamic process occurs also for the 18-electron complex 5 consisting in a dissociation-association equilibrium of the olefin.
