Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• transformations: copper(I)-catalyzed regiocontrolled three-component assembly of alkyne 8, THIQ segment 9, and benzaldehyde to yield 10, followed by tandem Strecker reaction and intramolecular cyclization to form 2,3-diaminobenzofuran 11. Subsequent gold(I)-mediated 6-endo hydroamination of 11 leads to the

• Strecker reaction and cyclization to form the 2,3-diaminobenzofuran moiety, and gold(I)-promoted cascade sequence via 6-endo hydroamination, spontaneous dehydrogenative oxidation followed by ring opening. Carbon numbering was assigned in accordance with natural products. The structure of 16 was determined

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• mechanism is energetically more favoured [34]. Two computed reaction pathways for the COBI-catalysed Strecker reaction (TS1 identical to allylation – COBI–imine complex) reported by Chen and Qiao in 2023 [38]. The position of homoallylic amines in the landscape of alkaloid and nitrogen compounds syntheses

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• Strecker reaction [44][45] where a cyanide, aldehyde, and amine react to afford α-aminonitriles. Compound 5c was converted to the deuterated amino acid 5d under acidic conditions. This finding opens up the possibility of scale-production of deuterium-labeled α-amino acids. Deuterated Strecker products are

• . No deuterium scrambling observed. Ugi-azide reaction products, no deuterium scrambling observed. Passerini products, no deuterium scrambling observed. aWater was used as solvent. Strecker reaction products (precursors to [D1]-α-amino acids), no deuterium scrambling was observed. aThe cyano-group was

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• Abstract This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with

• -benzoxazole [13] or different other acetohydrazines [14], complexation of phenothiazinyl-chalcone using diiron nonacarbonyl [15], and regioselective oxidation [16]. α-Aminonitriles are versatile synthetic intermediates that are readily obtainable by a Strecker reaction involving the addition of a cyanide

• of aldimine and ketoimine substrates under mild conditions [18]. Early studies reported a positive effect of sonication on the classical aminocyanation procedures. The reaction rate of the classical Strecker reaction using cyanide salts, amines and aromatic carbonyl derivatives [19] or piperidone [20

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• acid catalyst for this transformation. At room temperature, the product of this environmentally friendly Strecker reaction is nitrile derivative 53 (R2 = CN, Scheme 15, method A), while at reflux carboxamide 53 (R2 = CONH2, Scheme 15, method A) is obtained. Notoriously, aromatic amines 2 did not work

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• in forming hydrogen bonds with substrates. This may lead to activated forms of the substrates allowing the corresponding reaction to occur [9][10][11]. For example, Jacobsen and co-workers pioneered an effective chiral thiourea catalyst which was employed in an asymmetric Strecker reaction [12][13

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• -donating and -withdrawing substitutions on benzaldehydes or in benzoic acids have worked well under the mechano-chemical conditions [116]. In a multicomponent Strecker reaction the syntheses of α-aminonitriles are generally done by condensation of aldehydes, ammonia and hydrogen cyanide [117][118]. The

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• muraymycins (Scheme 5) [98]. A fully protected ureidomuraymycidine tripeptide was prepared through lactone opening followed by urea formation and a final Mitsunobu ring closure as key steps. A Strecker reaction of the benzylimine 34 followed by several steps afforded the alcohol 35. A thermal lactonisation as

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• -acylpyrroles are more reactive at the carbonyl unit and the tetrahedral intermediate is more stable than the Weinreb amides [208]. Based on their previous work on the Strecker reaction [209][210][211], Shibasaki and co-workers used a gadolinium-based catalyst for the 1,4-cyanation (Scheme 25). Overall, this

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

• Shinichi Yamabe Guixiang Zeng Wei Guan Shigeyoshi Sakaki Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103, JAPAN. Phone: +81-075-711-7907 10.3762/bjoc.10.184 Abstract The Strecker reaction of acetaldehyde, NH3, and HCN to afford

• (amino)-protonated aminonitrile which occurs with an ΔE≠ value of 34.7 kcal/mol. In the Strecker reaction, the proton transfer along the hydrogen bonds plays a crucial role. Keywords: amide intermediate; DFT calculations; hydrogen bonds; Strecker reaction; transition state; Introduction In 1850, Adolph

• alanine in the acidic solution. The traditional Strecker reaction gave racemic α-aminonitriles (mixtures of equal amounts of R and S forms), where an imine RCH=NH was considered to be the key intermediate [2]. Three typical reactions are presented in Scheme 1(b) [3]. In 1963, Harada reported the first

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

• Rajesh Munirathinam,
• Roberto Ricciardi,
• Richard J. M. Egberink,
• Jurriaan Huskens,
• Michael Holtkamp,
• Herbert Wormeester,
• Uwe Karst and
• Willem Verboom

Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194

• Strecker reaction by Wiles and Watts [13]. The dehydration of cinnamaldehyde oxime [18] was used as a model reaction to study the catalytic activity of a microreactor with gallium immobilized onto its channel walls (Scheme 1). Results and Discussion The catalytic polymer brush layer was first developed on

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

• be investigated (most notably the Strecker reaction) [2], but recent developments focus on cycloadditions [3], rare amino acids [4], chiral catalysis [5], etc. It is noteworthy, however, that two of the most widely applied methods for the introduction of the amine group – the Beckmann [6][7][8][9

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• aminoacetal formation. The chiral auxilliary can be removed by further treatment with DIBAL-H and Pb(OAc)4 (Scheme 9) [8]. The Strecker reaction, employing aldehydes or ketones and a cyanide source, is a very useful route for the preparation of α-aminonitriles 19 or 20. A general and efficient three-component

• diversity. Synthesis of imidazolinium salts. Access to the indenamine core. Synthesis of substituted tetrahydropyridines. Synthesis of more substituted tetrahydropyridines. Synthesis of chiral tetrahydropyridines. Preparation of α-aminonitrile by a catalyzed Strecker reaction. Synthesis of spiroacetals

Cobalt(II) chloride catalyzed one-pot synthesis of α-aminonitriles

• Surya K. De

Beilstein J. Org. Chem. 2005, 1, No. 8, doi:10.1186/1860-5397-1-8

• three- component condensation of aldehydes, amines, and potassium cyanide in acetonitrile in the presence of a catalytic amount of CoCl2 at room temperature. Introduction The addition of cyanide to imines (the Strecker reaction) [1] provides one of the most direct and viable routes for the synthesis of