Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• ethers of 3,6-diacetylcarbazole with p-benzoquinone (Scheme 1B) [49], the double Buchwald–Hartwig amination of 4,4'-biphenanthrene derivatives (Scheme 1C) [45] and a enantioselective Fischer indolization–oxidation protocol (Scheme 1D) [43]. Each method is not without drawbacks such as hardly available

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• ketones were used to synthesize new N,S-heterotetracenes, namely 9H-thieno[2',3':4,5]thieno[3,2-b]indoles by their treatment with arylhydrazines in accordance with the Fischer indolization reaction. Keywords: Fiesselmann thiophene synthesis; Fischer indole synthesis; N,S-heteroacene; thieno[3,2-b

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• from the biological evaluation to the chemistry of tryptophan analogues, the above described two categories were synthesized according to the Pictet–Spengler reaction or by Fischer indole synthesis [11][12][13][14]. However, Fischer indolization suffers from the lack of regioselectivity depending on

Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Mukesh E. Shirbhate

Beilstein J. Org. Chem. 2015, 11, 1514–1519, doi:10.3762/bjoc.11.165

• via Grignard addition, Fischer indolization and ring-closing metathesis as key steps. Keywords: cyclophane; Grignard reaction; Fischer indolization; ring-closing metathesis; Introduction Modern olefin metathesis catalysts enable a late stage ring-closing step starting with bisolefinic substrates

• cyclophanes the development of powerful and general synthetic methods is highly desirable. Herein, we report a new approach to thiophene- and indole-containing hybrid cyclophane derivatives via Grignard addition, Fischer indolization and RCM as key steps. Strategy The retrosynthetic strategy to the target

• cyclophane 1 containing the thiophene and indole moieties is shown in Figure 1. Here, we conceived thiophene-containing diolefin 3 as a possible synthon to assemble the target molecule 1 via 2. Route A involves an RCM of 3 followed by Fischer indolization of 2 (Figure 1). Alternatively, Fischer indolization

Hybrid macrocycle formation and spiro annulation on cis-syn-cis-tricyclo[6.3.0.0^2,6]undeca-3,11-dione and its congeners via ring-closing metathesis

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Rashid Ali

Beilstein J. Org. Chem. 2015, 11, 1123–1128, doi:10.3762/bjoc.11.126

• based macrocycle 6 involving Fischer indolization and ring-closing metathesis (RCM). Various spiro-polyquinane derivatives have been assembled via RCM as a key step. Keywords: aza-polyquiananes; Fischer indolization; macrocycles; ring-closing metathesis; spiropolyquinanes; Introduction Design and

• new strategy based on Fischer indolization and ring-closing metathesis as the key steps. To develop a simple synthetic methodology to aza-polycycles and spiropolycycles from readily available starting materials [47][48][49][50][51][52], bicyclic, tricyclic and pentacyclic diones (1–3) were identified

• shown that Weiss–Cook dione 1 [49][50][51] is a useful substrate for double Fischer indolization with a low melting mixture of L-(+)-tartaric acid and N,N′-dimethylurea (L-(+)-TA:DMU) [55] at 70 °C to generate an unusual Cs-symmetric diindole derivative along with the known C2-symmetric diindole [56