Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• 305-8577, Japan 10.3762/bjoc.20.100 Abstract The addition reaction of C60 with silylene 1, a silicon analog of carbene, yielded the corresponding bis-adduct 3. The structure of 3 was determined by single-crystal X-ray structure analysis, representing the first example of a crystal structure of a

• . Keywords: bis-adduct; C60; fullerene; silirane; silylene; Introduction The chemical functionalization of fullerenes has been exploited extensively from both fundamental and practical perspectives, elucidating their potential applications for biochemistry, nanomaterials sciences, and molecular electronics

• structures of bis-adduct isomers 3cis-2, 3cis-3, 3e, 3trans-1, 3trans-2, 3trans-3, and 3trans-4 were calculated by assuming the 6,6-silirane structures for addition sites. Calculation of 3cis-1 was not conducted because of its sterically clouded structure. Structural parameters around the addition sites of

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• single-cis conformation. Ando and co-workers prepared the symmetrical 1,4-dithiane 41 (Scheme 9a) [55], and amply illustrated the concept by reacting it in a [4 + 2] cycloaddition with a highly reactive diazo dienophile (Cookson’s reagent or 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD)) to afford the bis

• -adduct dithiin 42 in quantitative yield. Although 2,5-dimethylhexa-2,4-diene cannot possibly adopt a coplanar single-cis conformation, and is therefore completely unreactive in Diels–Alder reactions as a diene, its 1,4-dithiane-tethered version in 41 must show a sufficient proximity between the terminal

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• =N carbon is more electrophilic. Steric and electronic properties thus counteract and the overall selectivity of the reaction depends on a balance between both factors. Whilst chromatographic separation of the mixture of the monoadducts 12 + 13 from the starting material 3 and the bis-adduct 4 is

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• , a bis-adduct 12f was obtained in addition to trishydrazone 11f (Table 2, entry 4). Cyclization of trishydrazones 11 Upon treatment with acetic acid, trishydrazone 11b underwent a remarkable transformation to the tetraazaadamantane derivative 13b via intramolecular cyclotrimerization of C=N bonds

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• vinyl ketone (MVK) indicated that only around 60% of the starting aniline had converted, particularly at larger scales (>1 g). Two equivalents of MVK were required to effect full conversion, however, under these conditions the bis-adduct was formed in around 6–10% and this was difficult to remove by

• chromatography or distillation. Using one equivalent lowered the yield, but minimised bis-adduct formation, which allowed facile purification by short path distillation on larger scales. Compound 8 was functionalised to the tertiary alcohol 9 by a Grignard reaction with MeMgBr, which could be directly cyclised

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• studied. Results and Discussion Our strategy to polycycles involves a Diels–Alder reaction (DA) [23][24][25], a Grignard addition [26] and a RRM as key steps. To begin with, a double DA reaction of cyclopentadiene (1) with 1,4-benzoquinone (2) gave the known bis-adduct 3 [27][28]. Later, it was reacted

• this strategy, next we focussed on the preparation of an analogous bicyclo[2.2.2] system and to this end, the DA reaction of 1,3-cyclohexadiene (7) with 1,4-benzoquinone (2) furnished the known bis-adduct 8 [27][28], which on treatment with allylmagnesium bromide delivered diol 9. Later, O-allylation

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

• produced in 77% yield, and from hexaene 21 the mono-adduct 45 (49%). Finally, with heptaene 22 and nonaene 42 the adducts 46 and 47 were obtained in varying yields. In the latter case some decomposition of the product was noted during work-up and we isolated a TCNE bis-adduct, 48, for the first time in

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• oxalyl chloride (2.00 equiv) and catalytic DMF. Subsequent reaction with diamine 21 in the presence of pyridine (1.20 equiv) and catalytic DMAP over 24 h, according to previously reported reactions for similar keto acids [49], gave only the bis-adduct 24 and none of the desired piperazinone 23. By

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

• Olivier Debleds,
• Eric Gayon,
• Emmanuel Vrancken and
• Jean-Marc Campagne

Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99

• substitution reactions. BF3 vs AuCl3 in propargylic substitutions [25]. The use of bis-nucleophiles in direct propargylic substitutions. Tandem reactions from protected hydroxylamines and propargylic alcohols. P = Cbz, PhSO2. Tentative hydrolysis of bis-adduct 24a. Iron-catalyzed propargylic substitutions

Synthesis of oxa-bridged derivatives from Diels–Alder bis-adducts of butadiene and 1,2,3,4-tetrahalo-5,5-dimethoxycyclopentadiene

• Faiz Ahmed Khan and
• Karuppasamy Parasuraman

Beilstein J. Org. Chem. 2010, 6, No. 64, doi:10.3762/bjoc.6.64

• . We were interested in exploring the previously overlooked stereochemical outcome of the Diels–Alder reaction between 1a and 1,3-butadiene [15][16]. The bis-adduct obtained from 1a and gaseous 1,3-butadiene was previously assigned as “endo, exo-bis(7,7-dimethoxy-1,2,3,4-tetrachloronorborn-2-en-5-yl

• clarity]. 1H NMR chemical shifts (in parentheses) and coupling constants (J) for the three interacting protons (H5, H6, and H6’ ; for the sake of convenience, numbering sequence of mono-adducts is adopted) of the bis-adducts 6 and 13. Transition state models for the bis-adduct formation. Diels–Alder bis

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

• Markus Etzkorn,
• Jacob C. Timmerman,
• Matthew D. Brooker,
• Xin Yu and
• Michael Gerken

Beilstein J. Org. Chem. 2010, 6, No. 39, doi:10.3762/bjoc.6.39

• cyclohexadiene (5) with ketal 7a furnished exclusively the syn-bis-adduct 8a [20] which was then converted to the canary-yellow tetraketone 10 by Khan’s original RuCl3-catalyzed oxidation protocol [21][22][23] since Chou’s “optimized” procedure was somewhat capricious in our hands. The twofold condensation with

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• 199 to 200 in the presence of InCl3 afforded the bis-adduct, anti-diol 201. The derived tosylate 202 was converted to the bis-THF core unit 203 upon treatment with TBAF. Oxidation to aldehyde 204 followed by InCl3-promoted addition of the (S)-allylic stannane 205 gave the anti adduct 206. Removal of

• employed the (R)-α-OSEM allylic stannane 261 reaction with the dialdehyde 262 obtained from (S,S)-diethyl tartrate to afford the bis-adduct 263 (Scheme 36). Treatment of 263 with TBAF led to the core bis-THF intermediate, diol 264. Mono tosylation and subsequent hydrogenolysis with LiBEt3H gave alcohol 265