Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• as depicted in Figure 1, and named (+)-ximaocavernosin P. Compounds 4 and 5 showed NMR data diagnostic of tetrahydronaphthalene-bearing cadinane-type sesquiterpenoids, in line with the co-occurring compounds 6 and 7. In addition, 4 and 5 as optically inactive white powder implied the possibility that

• new. Compounds (+)-1, 2, and 3 share a common gem-dimethylcyclopropyl unit, belonging to aromadendrane- and aristolane-type sesquiterpenoids, respectively. Whereas compounds 4–7 are a small group of cadinane-type sesquiterpenoids bearing a tetrahydronaphthalene system, which are produced in nature

Selective benzylic C–H monooxygenation mediated by iodine oxides

• Kelsey B. LaMartina,
• Haley K. Kuck,
• Linda S. Oglesbee,
• Asma Al-Odaini and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

• proton coupled electron transfer (PCET) type mechanism. Additionally, as shown in Figure 2, 1,2,3,4-tetrahydronaphthalene was functionalized in poor yield (23%) to its acetate 3g if exposed to reaction conditions at lower temperatures (60 °C) than were used for other substrates. At 100 or 150 °C, only

• aromatization was observed, suggesting that monooxygenated products are able to react further. We propose that acetoxylated tetrahydronaphthalene eliminates acetic acid to yield dihydronaphthalene, which can be further oxidized by two electrons to yield the stable naphthalene ring. Minisci and co-workers also

• reported aromatization upon oxidation of tetrahydronaphthalene using an acetoxylation system similar to that reported in this work [57]. While the methodology described in this work is tolerant of molecular functionality with moderate oxidative stability such as esters and nitrogen-containing heterocycles

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• diiodobenzene 11 using allylboronate ester 12 via a SM-type allylation sequence [32]. Next, compound 13 was exposed to Grubbs 1st generation (G-I) catalyst 1 to effect the ring-closure to produce tetrahydronaphthalene derivative 14 (92%). Subsequently, aromatization of compound 14 was accomplished with 2,3

The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp²)/C–H(sp) coupling under mild conditions

• Wei Zhu,
• Bao Wang,
• Shengbin Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 1624–1631, doi:10.3762/bjoc.11.177

• -substituted benzamides occurred predominantly at less sterically congested sites (3j, 3k). A ortho-substituted and a tetrahydronaphthalene derivative worked well, respectively, and provided moderate yields (3l, 3m). We also tested a variety of terminal alkynes as coupling partners with N-(quinolin-8-yl

Trogopterins A–C: Three new neolignans from feces of Trogopterus xanthipes

• Soyoon Baek,
• Xuikui Xia,
• Byung Sun Min,
• Chanil Park and
• Sang Hee Shim

Beilstein J. Org. Chem. 2014, 10, 2955–2962, doi:10.3762/bjoc.10.313

• )phenyl)propanoate (2), ((1RS,2RS,3RS)-6-hydroxy-2-(3-hydroxyphenyl)-1,2,3,4-tetrahydronaphthalene-1,3-diyl)dimethanol (3), ((R)-3,3'-(3-hydroxypropane-1,2-diyl)diphenol (4) [13], 8β-hydroxy-3-oxopimara-15-ene (5) [14], 9β-hydroxy-9(11),13-abietadien-12-one (6) [15], and ent-pimar-15-en-9α,19-diol (7) [16

• , H-8, and H-8′ are within 3 Å when two hydroxymethylene groups and a hydroxyphenyl group in compound 3 are on the same face of the molecule. Thus, the structure of compound 3 was determined to be ((1RS,2RS,3RS)-6-hydroxy-2-(3-hydroxyphenyl)-1,2,3,4-tetrahydronaphthalene-1,3-diyl)dimethanol and named

Organobase-catalyzed three-component reactions for the synthesis of 4H-2-aminopyrans, condensed pyrans and polysubstituted benzenes

• Moustafa Sherief Moustafa,
• Saleh Mohammed Al-Mousawi,
• Maghraby Ali Selim,
• Ahmed Mohamed Mosallam and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2014, 10, 141–149, doi:10.3762/bjoc.10.11

• -oxo-5-phenyl-3H-isoindole-4-carboxylate (40). Keywords: aminopyranes; arylbenzoic acid; DABCO; L-proline; multicomponent; tetrahydronaphthalene; three-component reaction; Introduction The reaction of arylidenemalononitriles with active methyl and methylene compounds was extensively utilized for the

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• '-indene] (75a) and 5-hydroperoxy-3',4'-dihydro-2'H-spiro[[1,2]dioxolane-3,1'-naphthalene] (75b), were synthesized by the ozonolysis of 1-allyl-1-hydroperoxy-2,3-dihydro-1H-indene (72a) and 1-allyl-1-hydroperoxy-1,2,3,4-tetrahydronaphthalene (72b), respectively, in an Et2O/CF3CH2OH system (2:1). The

• -tetrahydronaphthalene (144) with singlet oxygen via the formation of 4a-hydroperoxy-1,4,4a,5-tetrahydronapthalene (145) gives hydroperoxide-containing bromonium cation 147 as the intermediate, which undergoes cyclization to form 1,2-dioxolane-containing 7-bromo-4,5,10,11-tetraoxatetracyclo[7.2.2.13,6.03,9]tetradec-12

Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

• ]. For example, they are often used to construct substituted tetrahydronaphthalene skeletons in the presence of metal catalysts such as Pd [9][10], Ir [11][12][13][14][15], Rh [16][17][18][19][20][21] and Cu [22]. However, their reactivity in the presence of gold catalysts has been rarely reported [23

Development of peptidomimetic ligands of Pro-Leu-Gly-NH₂ as allosteric modulators of the dopamine D₂ receptor

• Swapna Bhagwanth,
• Ram K. Mishra and
• Rodney L. Johnson

Beilstein J. Org. Chem. 2013, 9, 204–214, doi:10.3762/bjoc.9.24

• β-turn that is mimicked is dictated by the chirality of C-3. Lactams 1, 2, 4–6, and 9 (Figure 2) were active in enhancing the binding of the dopamine receptor agonist 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN) to dopamine receptors, while 3, 7, and 8 were inactive [19][20]. The

β-Hydroxy carbocation intermediates in solvolyses of di- and tetra-hydronaphthalene substrates

• Jaya S. Kudavalli and
• Rory A. More O'Ferrall

Beilstein J. Org. Chem. 2010, 6, 1035–1042, doi:10.3762/bjoc.6.118

• cis and trans isomers, kcis/ktrans = 1800 in aqueous acetonitrile. This mirrors the behaviour of the acid-catalysed dehydration of cis- and trans-naphthalene-1,2-dihydrodiols to form 2-naphthol, for which kcis/ktrans = 440, but contrasts with that for solvolysis of tetrahydronaphthalene substrates, 1

• -chloro-2-hydroxy-1,2,3,4-tetrahydronaphthalenes, for which kcis/ktrans = 0.5. Evidence is presented showing that the trans isomer of the dihydro substrates reacts unusually slowly rather than the cis isomer unusually rapidly. Comparison of rates of solvolysis of 1-chloro-1,2,3,4-tetrahydronaphthalene and

• cis-and trans-1-chloro-2-hydroxy-1,2,3,4-tetrahydronaphthalene (1-chloro-2-tetralol, 4), which are similar in structure but lack a 3,4-double bond and yield carbocations which cannot undergo deprotonation to form aromatic products. Finally, to allow the influence of the β-hydroxy group on the rate of