α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• . Importantly, the protocol was found to be similarly applicable with enoates 8b (Table 3, entry 6) and 8c (entry 7) having tert-butyl and benzyl ester groups, which, as the methyl ester unit, are typical in the context of amino acid synthesis. ZnBu2 was also amenable to 1,4-addition (Table 3, entry 8), but not

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• energy consumption and hence lead to more effective and sustainable processes [4][5][6]. MCRs found numerous applications, i.e., in combinatorial chemistry, target oriented synthesis or polymer science [6][7][8]. The most important MCRs are the Strecker amino acid synthesis (1850), the Hantzsch

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• were prepared by reductive amination of γ-aminophosphonyl ketones using sodium borohydride [41], or by conjugate addition of diethyl methylphosphonite to 2-cyclohexenone followed by Bucherer–Bergs amino acid synthesis [42]. Another synthetic approach for a series of α-fluorinated-γ-aminophosphonates

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• enduracididine Although several synthetic approaches to enduracididine and its derivatives have been published, the discovery of teixobactin (17) has reignited interest in the synthesis of this unnatural amino acid. Synthesis of enduracididine by Shiba et al.: The first diastereoselective synthesis of

Proton transfers in the Strecker reaction revealed by DFT calculations

• Shinichi Yamabe,
• Guixiang Zeng,
• Wei Guan and
• Shigeyoshi Sakaki

Beilstein J. Org. Chem. 2014, 10, 1765–1774, doi:10.3762/bjoc.10.184

• Strecker reported a reaction that affords alanine from acetaldehyde, ammonia and hydrogen cyanide [1]. The original form of Strecker amino acid synthesis is shown in Scheme 1(a). In this reaction, the aldehyde reacts with hydrogen cyanide to form an aminonitrile, which undergoes hydrolysis to afford

Synthesis of enantiomerically pure (2S,3S)-5,5,5-trifluoroisoleucine and (2R,3S)-5,5,5-trifluoro-allo-isoleucine

• Holger Erdbrink,
• Elisabeth K. Nyakatura,
• Susanne Huhmann,
• Ulla I. M. Gerling,
• Dieter Lentz,
• Beate Koksch and
• Constantin Czekelius

Beilstein J. Org. Chem. 2013, 9, 2009–2014, doi:10.3762/bjoc.9.236

• helical assemblies, these two properties were examined for L-5-F3Ile, as one of the possible fluorinated analogues of proteinogenic isoleucine. Results and Discussion Amino acid synthesis We have recently described a new method for the conjugate trifluoromethylation of α,β-unsaturated acyloxazolidinones

Approaches to α-amino acids via rearrangement to electron-deficient nitrogen: Beckmann and Hofmann rearrangements of appropriate carboxyl-protected substrates

• Sosale Chandrasekhar and
• V. Mohana Rao

Beilstein J. Org. Chem. 2012, 8, 1393–1399, doi:10.3762/bjoc.8.161

• acid (possibly selectively). These conversions would be of considerable value in peptide synthesis strategy. Conclusion Rationally designed, controlled approaches to α-amino acid synthesis via two classical reactions have been demonstrated. The key step is based on the Beckmann and the Hofmann

Synthesis of new C^α-tetrasubstituted α-amino acids

• Andreas A. Grauer and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 5, doi:10.3762/bjoc.5.5

• aldehydes are prone to give aldol products under the reaction conditions used, we were able to obtain the target cyclic amino acids in low to moderate yields and in some cases with good diastereoselectivity. Keywords: amino acid synthesis; Cα-tetrasubstituted α-amino acids; unnatural amino acids

• spectra of all new compounds see Supporting Information File 1. The sulfonium salt 1 was synthesized according to a known literature procedure [20]. General Procedure for the tetrahydrofuran amino acid synthesis (GP 1) In an oven dried Schlenk flask under nitrogen atmosphere the sulfonium salt (0.125–1.5