Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• enables the synthesis of structurally distinct cyclic derivatives which are difficult to access by other methodologies, using an efficient and atom-economical path from simple precursors. In recent years several asymmetric catalytic cyclization strategies have been accomplished for the construction of N

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• through a range of synthetic methodologies suggested recently. Cyclization strategies [35][36][37][38][39][40][41][42][43][44][45] as well as cycloaddition/cyclocondensation techniques [46][47][48][49][50][51] represent those with hetero-ring construction. Alternative approaches rely on a peripheral

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• . Keywords: 5-8 bicycle; cyclization strategies; terpenes; Introduction Terpene compounds represent the largest and most diversified class of secondary metabolites. They are present in all organisms and their structure can vary from simple terpenes (C10 skeleton) to polymers (example of rubber) thanks to

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• -azaphospholidine and 1,2-azaphospholine rings (Figure 2). This review includes the synthesis of 1,2-azaphospholidine and 1,2-azaphospholine 2-oxides/sulfides and their fused derivatives. Review Synthesis of 1,2-azaphospholidine 2-oxide derivatives via cyclization Various cyclization strategies have been developed

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• Prins cyclization strategies, covering the literature reports of the last twenty years (from 2000 to 2019), with an aim to give an overview on exciting advancements in this area and designing new strategies for the total synthesis of related natural products. Keywords: asymmetric; natural products

• Prins and related cyclization strategies along with the discussion on the general mechanistic part. We sincerely hope that this review will deliver a snapshot of the up-to-date state of the inventiveness in this field, and most importantly, it will give an inspiration to the reader to take up the

• of this catalyst was the key to a successful transformation. This reaction proceeded via a Prins cyclization mechanism, activated by chiral acid 319. Conclusion Prins cyclization strategies have been proven as a reliable and robust method for the stereoselective construction of THP rings. Many of

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• analogy to nature’s biosynthetic strategies outlined above, cationic, Diels–Alder, oxidative, and radical cyclization strategies have been successfully applied in total syntheses of terpenoids [53]. In addition, chemists are currently creatively exploring means to mimic classical terpene cyclases and

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• synthesis of chiral benzo-annulated heterocycles are relatively limited [22][23][24][25][26]. In this paper, we describe our efforts toward the synthesis of 2, 3 and 5 using different cyclization strategies. To the best of our knowledge, nebivolol or its intermediates have never been synthesized using

• of (S,R,R,R)-nebivolol, we have extensively studied different cyclization strategies. The construction of 2-substituted chroman derivatives using phenolic hydroxy-mediated intramolecular ring opening of syn-2,3-diol ester-derived cyclic orthoester or intramolecular SNAr reaction of a triol containing

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• cyclic constrained peptidomimetics, the acyclic products have to be cyclized via additional cyclization strategies. This is possible via incorporation of bifunctional substrates into the initial IMCR. Examples of such bifunctional groups are N-protected amino acids, convertible isocyanides or MCR

• cyclic peptide mimics (ranging from four- to seven-membered rings), medium-sized cyclic constructs or peptidic macrocycles (>12 membered rings). This review describes the developments since 2002 of IMCRs-cyclization strategies towards a wide variety of small cyclic mimics, medium sized cyclic constructs

• , several cyclization strategies have been utilized in order to obtain cyclic constructs. For example, the incorporation of cyclic imines immediately gives cyclic MCR-products, whereas other strategies make use of unreactive, convertible or protected functional Ugi-substrates that can be cyclized via