Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• formation of unsaturated products, often in the form of polyenes or alkynes [28]. The non-standard transition method found here in the acenaphthene–acenaphthylene pair is a previously unknown approach for the synthesis of acenaphthylenes based on tele-elimination (see also below). Changing the nucleophile

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• -pyrone, simplified analogues of tridachiapyrone B such as 19. Without requiring the construction of polyenes, the route is enabled by key transformations such as the formal crotylation of α,α’-dimethoxy-γ-pyrone, the Robinson-type annulation of a sensitive aldehyde and 1,2-addition to 2,5

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• compounds possess are unsaturated polyenes, while the acyl chains of the nanangenines are fully saturated. As noted earlier, 2–4 were previously reported as unnamed metabolites from Aspergillus sp. IBWF002-96 [4][5], which has an internal transcribed spacer (ITS) sequence that shares 100% identity with an

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• -isomers more favorable [40]. Vinylphosphonium salts can also be directly converted into the corresponding ylides by potassium tert-butoxide and subjected to the Wittig reaction as described by Yamamoto et al. (Scheme 25). The transformation resulted in polyenes 35 of Z-configuration in a relatively low

Sulfation and amidinohydrolysis in the biosynthesis of giant linear polyenes

• Hui Hong,
• Markiyan Samborskyy,
• Katsiaryna Usachova,
• Katharina Schnatz and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2017, 13, 2408–2415, doi:10.3762/bjoc.13.238

• from Streptomyces mediocidicus), are near-identical giant linear polyenes apparently constructed from, respectively, a 4-guanidinobutanoate or 4-aminobutanoate starter unit and 27 polyketide extender units, and bearing a specific O-sulfonate modification at the C-29 hydroxy group. We show here that

•  1), implying that these amidinotransferases operating on linear and macrocyclic polyenes do not have overlapping substrate specificities. Sequence alignment of amidinohydrolase Medi4948 with authentic ureohydrolases in the Protein Data Bank (PDB) (Figure S2, Supporting Information File 1) revealed

• in a genome-led approach to the uncovering of novel enzymology in the biosynthetic pathways to antibiotic natural products [23][24][25][26]. Here, we have used in-house whole-genome sequencing to characterise the closely-related gene clusters to the sulfated antifungal linear polyenes clethramycin

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• an optimized C–C cross-coupling sequence with a Suzuki cross-coupling reaction as key step. Keywords: antibiotics; polyenes; polyketides; Stille reaction; Suzuki reaction; total synthesis; Introduction The elansolids are metabolites from the gliding bacterium Chitinophaga sancti (formerly

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• 77006, USA 10.3762/bjoc.12.135 Abstract Ring-whizzing was investigated by hybrid DFT methods in a number of polyene–Pt(diphosphinylethane) complexes. The polyenes included cyclopropenium+, cyclobutadiene, cyclopentadienyl+, hexafluorobenzene, cycloheptatrienyl+, cyclooctatetraene

• polyene–Pt(dpe) examples The most simple of the cyclic polyenes is the cyclopropenium cation. Its LUMO is a degenerate par of π orbitals, labeled e”A and e”S in Figure 3. It is easy to see that e”A interacts with the b2 orbital of ML2 at an η2 geometry. Indeed this is the computed group state for C3H3–Pt

Tandem processes promoted by a hydrogen shift in 6-arylfulvenes bearing acetalic units at ortho position: a combined experimental and computational study

• Mateo Alajarin,
• Marta Marin-Luna,
• Pilar Sanchez-Andrada and
• Angel Vidal

Beilstein J. Org. Chem. 2016, 12, 260–270, doi:10.3762/bjoc.12.28

• , in comparison with those of TS1-A and TS1-C, could be also decisive in accounting for the differences in the respective energy barriers. 2) Concerning the two key polyenes 10a and 11a, precursors of the tricycles 12a and 13a, respectively, the computed energy barriers of this study show that i) 10a

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• compounds even at 0 °C. It was also examined in more demanding systems such as conjugated dienes and polyenes. The catalyst is stable, storable and easy to purify. Keywords: chromane derivatives; metathesis catalyst; nitrogen heterocycles; olefin metathesis; Ru-carbene; Introduction Olefin metathesis is

• potency of the new catalyst 9 was tested not only in standard, model metathesis reactions but was also examined in more demanding systems, such as conjugated dienes and polyenes (Table 4). The CM reaction between alkene and diene (or polyene) often suffers from low regio- and stereoselectivity control

• the π-complex and rutenacyclobutane intermediate (Figure 3), which promotes the metathesis reaction on the C2–C3 double bond. The formation of four- and five-membered chelates has been postulated previously [33][34]. The CM reactions of polyenes, β-carotene and retinyl acetate with ethyl 3-methylhexa

The chemical behavior of terminally tert-butylated polyolefins

• Dagmar Klein,
• Henning Hopf,
• Peter G. Jones,
• Ina Dix and
• Ralf Hänel

Beilstein J. Org. Chem. 2015, 11, 1246–1258, doi:10.3762/bjoc.11.139

• we described [2] a general synthesis of a series of terminally substituted, conjugated polyenes, 2, beginning with the diene and ending with the decatriene (Scheme 1). We also reported the X-ray structures of compounds with n = 1, 2, 3, 4, 5 and 7 and discussed the structural similarities, in

• particular the distortions associated with the bulky tert-butyl groups. For all these hydrocarbons, di-tert-butylketone (1) served as the starting material, which was chain-elongated by preparative sequences involving standard Wittig, Wittig–Horner and McMurry coupling reactions. Nearly all of the polyenes 2

• levels. The polyenes 2 stabilized by terminal tert-butyl substituents. The catalytic hydrogenation of diene 3. The catalytic hydrogenation of triene 7. Addition of bromine to model dienes. Bromine addition to diene 3 and triene 7. Bromine addition to the higher oligoenes 19–22. Epoxidation of triene 7

Cyclodextrin–polysaccharide-based, in situ-gelled system for ocular antifungal delivery

• Anxo Fernández-Ferreiro,
• Noelia Fernández Bargiela,
• María Santiago Varela,
• Maria Gil Martínez,
• Maria Pardo,
• Antonio Piñeiro Ces,
• José Blanco Méndez,
• Miguel González Barcia,
• Maria Jesus Lamas and
• Francisco.J. Otero-Espinar

Beilstein J. Org. Chem. 2014, 10, 2903–2911, doi:10.3762/bjoc.10.308

• lead to loss of vision. Candida albicans is one of the most widespread fungal pathogens involved in fungal keratitis [1][2]. The most common antifungal treatments include the use of polyenes and azoles; however, a significant treatment failure rate exists with these pharmacological agents [3

One-pot three-component synthesis and photophysical characteristics of novel triene merocyanines

• Christian Muschelknautz,
• Robin Visse,
• Jan Nordmann and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51

• -substituted polyenes, has become increasingly interesting due to their fine-tunable electronic distribution [10]. For instance, merocyanines are perfectly suited for developing molecule-based non-linear optical materials and photovoltaic chromophores [11]. Classically, these push–pull chromophores always have

Zirconoarylation of alkynes through p-chloranil-promoted reductive elimination of arylzirconates

• Xiaoyu Yan,
• Chao Chen and
• Chanjuan Xi

Beilstein J. Org. Chem. 2014, 10, 528–534, doi:10.3762/bjoc.10.48

• dienes and polyenes [44][50][51][52][53][54][55][56][57]. When triphenylvinylzirconocene 4a was reacted in the presence of CuCl and TCQ, the 1,1,2,3,4,4-hexaphenyl-1,3-butadiene (5) was formed in 43% isolated yield (Scheme 5). It is noteworthy that in this reaction two molecular alkynes and two

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• the double 1,4-diene (Figure 2). Notwithstanding the successful syntheses of ripostatins, preparation of configurationally defined skipped polyenes (1,4-dienes and higher homologues) remains a significant challenge in organic chemistry. The doubly allylic protons found in these structures may be

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• coupling reaction of 1,2-allenoate, organozinc reagent, and ketone. Proposed mechanism for a rhodium-catalyzed arylzincation of allenes. Synthesis of skipped polyenes by iterative arylzincation/allenylation reaction. Synthesis of 1,4-diorganomagnesium compound from 1,2-dienes. Synthesis of tricyclic

Enantioselective total synthesis of (R)-(−)-complanine

• Krystal A. D. Kamanos and
• Jonathan M. Withey

Beilstein J. Org. Chem. 2012, 8, 1695–1699, doi:10.3762/bjoc.8.192

• methods for the preparation of homoconjugated all-Z-polyenes. In the latter, metal-mediated coupling of 1-alkynes and propargylic halides is generally employed, with copper (I) alkynides being the least prone to isomerization, polymerization or multiple alkylation. Of the several methods reported, a

Fluorescent hexaaryl- and hexa-heteroaryl[3]radialenes: Synthesis, structures, and properties

• Antonio Avellaneda,
• Courtney A. Hollis,
• Xin He and
• Christopher J. Sumby

Beilstein J. Org. Chem. 2012, 8, 71–80, doi:10.3762/bjoc.8.7

• interesting physical properties and chemical reactivity [1][2]. The parent dendralenes are acyclic cross-conjugated polyenes (Figure 1a) whose relative instability had prevented them from being successfully produced in large quantities [3]. Recently, Sherburn reported the synthesis of the first six members of

• the parent dendralene series on gram scales [4][5][6][7][8]. Initial studies have shown that the odd-numbered dendralenes are much more chemically reactive than the even-numbered dendralenes. In turn, radialenes are cyclic cross-conjugated polyenes which exhibit a general formula of C2nH2n and contain

Photocycloadditions and photorearrangements

• Axel G. Griesbeck

Beilstein J. Org. Chem. 2011, 7, 111–112, doi:10.3762/bjoc.7.15

• transfer modes. Photocycloaddition reactions can be performed in numerous ways using unsaturated substrates such as carbonyl compounds, Michael acceptors, monoalkenes, polyenes, or aromatic substrates leading to complex products that can be used in subsequent transformations. The carbonyl-ene