Synthetic and mechanistic studies in enantioselective allylic substitutions catalysed by palladium complexes of a modular class of axially chiral quinazoline-containing ligands

Carroll, Anne-Marie; McCarthy, Marie; Lacey, Patrick M.; Saunders, Cormac P.; Connolly, David; Farrell, Annette; Rokade, Balaji V.; Goddard, Richard; Fristrup, Peter; Norrby, Per‐Ola; Guiry, Patrick J.

doi:10.1016/j.tet.2019.130780

Cited by 9 publications

(6 citation statements)

References 84 publications

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“…Additional references cited within the Supporting Information. [33][34][35][36][37][38][39][40][41][42][43][44][45][46] Scheme 2. Reactions were carried out on 0.6 mmol scale using 1.0 equiv.…”

Section: Supporting Informationmentioning

confidence: 99%

Supported Ionic Liquid Phase (SILP) Allylic Alkylation of Amines in Continuous Flow

et al. 2023

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We present the use of Pd‐complex‐containing supported ionic liquid phases (SILPs) as a novel approach for continuous‐flow allylic alkylation of N‐nucleophiles. This immobilization strategy gave simple access to air‐tolerating catalyst frameworks, providing rapid and convenient access to various achiral and chiral N‐allylation products. Under optimized conditions, the flow‐reaction could be maintained for 3.5 hours with constant product output; meanwhile, only a marginal 0.7 wt % of ionic liquid leaching and no detectable palladium‐complex leaching could be observed.

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Section: Supporting Informationmentioning

confidence: 99%

Supported Ionic Liquid Phase (SILP) Allylic Alkylation of Amines in Continuous Flow

et al. 2023

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“…[c] Absolute configuration determined by comparison with literature values. [21] [d] 15-Crown-5 added.…”

Section: Entrymentioning

confidence: 99%

“…IR (neat): 2967, 2932, 2872 1702, 1559, 1512, 1473, 1380. (11), 155 (23), 148 (12), 141 (4), 133 (4), 120 (4), 102 (5), 93 (6), 86 (3), 78 (10), 67 (130), 51 (21) (20). 3-Chloro-2,5-di(propan-2-yl)pyrazine (18; 5.50 g, 27.7 mmol) was added through a syringe to a solution of Pd(PPh 3 ) 4 (1.60 g, 1.38 mmol) in dry, degassed 1,2-dimethoxymethane (80 mL) and stirred for 15 min under an atmosphere of nitrogen.…”

Section: -Chloro-25-di(propan-2-yl)pyrazinementioning

confidence: 99%

“…The precipitate was washed with CH 2 Cl 2 , the organic layers were combined, washed with saturated brine, water and dried over sodium sulphate. The solvent was removed in vacuo to leave a brown oil which was purified by silica gel column chromatography (CH (21). Using a modification of a procedure by Eisenbraun, [63] boron tribromide (32 mL, 1 M) was added slowly through a syringe to a solution of 3-(2methoxynaphthalen-1-yl)-2,5-di(propan-2-yl)pyrazine (20; 6.70 g, 20.9 mmol) in dry CH 2 Cl 2 (120 mL).…”

Section: -Chloro-25-di(propan-2-yl)pyrazinementioning

confidence: 99%

“…The reaction was kept at this temperature for 6 d after which time the solvent was removed in vacuo leaving a green oil. This was purified using silica gel column chromatography (hexanes/AcOEt (19), 339 (4), 208 (21), 183 (30), 152 (6), 108 (16), 77 (12), 53 (13), 43 (43). Anal.…”

Section: -Chloro-25-di(propan-2-yl)pyrazinementioning

confidence: 99%

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The Preparation and Resolution of Novel Axially Chiral Pyrazine‐Containing P,N Ligands for Asymmetric Catalysis and Their Application in Palladium‐Catalysed Allylic Substitution

Guiry

Kelly

Goddard

2021

Helvetica Chimica Acta

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Dedicated with respect and admiration to Peter Kündig, a gentleman and an inspirational chemist, on the occasion of his 75th birthdayThe design and synthesis of two novel pyrazine-containing ligands, 3,6-diisopropyl-Pyrazinap and NpÀ Cy-Pyrazinap, has been described. Their synthesis was accomplished in six and nine steps, respectively, in which the key steps were the formation of the biaryl linkage through a Suzuki cross-coupling reaction and the formation of the aryl to phosphorus bond employing nickel catalysis. Both ligands were resolved through the formation of diastereomeric palladacycles and in the case of the isolated diastereomer formed from 3,6-diisopropyl-Pyrazinap, an X-ray crystal structure showed the axial chirality to possess (S)-configuration. The two enantiopure ligands were applied to the palladium-catalysed allylic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate and afforded conversions of up to 100 % and 99 % with enantioselectivities of up to 92 % ee and 78 % ee, respectively. A series of 1,1,3-triphenylallyl and 1,3-diphenylallyl palladium complexes were prepared and their solution structures and dynamic behaviour elucidated by 2D-COSY and NOESY NMR spectroscopic experiments.

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Nucleophilic Aliphatic Substitution 2020

Moloney,

Moloney

2024

Organic Reaction Mechanisms 2020

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Synthetic and mechanistic studies in enantioselective allylic substitutions catalysed by palladium complexes of a modular class of axially chiral quinazoline-containing ligands

Cited by 9 publications

References 84 publications

Supported Ionic Liquid Phase (SILP) Allylic Alkylation of Amines in Continuous Flow

Supported Ionic Liquid Phase (SILP) Allylic Alkylation of Amines in Continuous Flow

The Preparation and Resolution of Novel Axially Chiral Pyrazine‐Containing P,N Ligands for Asymmetric Catalysis and Their Application in Palladium‐Catalysed Allylic Substitution

Nucleophilic Aliphatic Substitution 2020

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