Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• range of less widely applicable strategies have been developed as well [17][18][19][20][21][22]. The above-mentioned methods focus on the synthesis of α-alkyl-amino acids. Moving to α-aryl-amino acids, the Clayden group published an excellent asymmetric α-arylation method to access quaternary amino

• acids with high enantiomeric purity [23]. The synthesis of formally glycine-derived tertiary α-aryl-amino acids is much less developed. The most common strategy for obtaining these substrates is by lithiation of an aromatic ring followed by coupling with a glycine derivative (Scheme 1a). For example

• reagents, rendering our approach well-suited for both industrial and academic settings. The synthesized amino esters were engaged in a three-step on-DNA validation protocol, demonstrating their possible application for DEL production. Known and improved synthetic strategies to access α-(hetero)aryl-amino

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

• Armin de Meijere,
• Sergei I. Kozhushkov,
• Dmitrii S. Yufit,
• Christian Grosse,
• Marcel Kaiser and
• Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

• complicated problem. "State of the art" peptide coupling methodology [59][60] allows one to prepare almost any peptides, that do not contain extremely sterically congested fragments such as α,α-dialkyl-substituted amino acids, N-alkyl amino acids or even the more challenging N-aryl amino acids. With a proper

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• architectures designed by cross-coupling strategies with the introduction of an amino acid functionality on 7-azaindole, result in new scaffolding. N-aryl-amino acids are reported as important synthetic intermediates and structural motifs for various drug-development programs by various medicinal and process

Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

• Elizabeth P. Jones,
• Peter Jones,
• Andrew J. P. White and
• Anthony G. M. Barrett

Beilstein J. Org. Chem. 2011, 7, 1570–1576, doi:10.3762/bjoc.7.185

• . Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave the corresponding valine dipeptides from bulkier bislactims. Keywords: aryl amino acids; arynes; asymmetric; multicomponent; quaternary; Introduction

• Schöllkopf’s bislactim ether 1 [12] to substituted arynes 2, which, following hydrolysis of the syn-adducts 3, provided α-aryl amino acids 4 with moderate to high enantioselectivities (Scheme 2) [13]. The arynes were produced by a directed ortho-metallation [14] and an elimination sequence, and after attack of

• methodology to a multicomponent system, we considered that quenching the key aza-enolate intermediate with an electrophile, rather than a proton source, should provide quaternary Schöllkopf adducts 6 (Scheme 4). The potential utility of chiral α-quaternary α-aryl amino acids in medicinal chemistry is diverse