A new synthesis of 2-(hetero)aryl-substituted pyrazines

Kodimuthali, Arumugam; Chary, Bathoju Chandra; Prasunamba, Padala Lakshmi; Pal, Manojit

doi:10.1016/j.tetlet.2009.01.110

Cited by 10 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A report by Pal opens the potential for an alternative approach to the biaryl coupling, as their report details the Lewis acid promoted coupling of 2chloropyrazine with arenes, such as 2-naphthol. [58] This approach could shorten the route outlined herein by two steps (formation of (2-methoxynaphthalen-1yl)boronic acid (19) and the demethylation step), although Pal's report does not include any substituted pyrazines.…”

Section: Ligand Synthesismentioning

confidence: 99%

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

View full text Add to dashboard Cite

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.

show abstract

Section: Ligand Synthesismentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…This methodology has two main drawbacks. First, the observed yields starting from aryl ketones are much lower than those obtained when starting from aldehydes. , Second, the Knoevenagel condensation requires a large library of both substituted aryl ketones and TZD to access an important range of compounds. Our study aimed to overcome such difficulties, and we report herein on our work concerning the development of the 6-functionalization of the BTZD scaffold (for numbering, see Scheme ), which enables the introduction of a wide functional diversity starting from three easily accessible building blocks.…”

Section: Introductionmentioning

confidence: 99%

Unexplored Vinylic-Substituted 5-Benzylidenethiazolidine-2,4-diones: Synthesis and DFT/NMR Stereochemical Assignment

et al. 2023

View full text Add to dashboard Cite

By exploring an efficient and versatile method for the 6-functionalization of its scaffold, we investigated the opening of a new chemical space around benzylidenethiazolidine-2,4-dione (BTZD). The 6-chloro- and 6-formyl BTZD obtained in two steps starting from 5-lithioTZD were selected as key intermediates and involved in a Pd-catalyzed cross-coupling or Wittig olefination. A variety of aryl, heteroaryl, or alkenyl substituents was successfully introduced on the vinylic position of BTZD, and particular attention was paid to elucidate the stereochemistry of the benzylidene derivatives by using a combined DFT/NMR study.

show abstract