Organoboron Derivatives of 1,8-Bis(dimethylamino)naphthalene: Synthesis, Structure, Stability, and Reactivity

Bardakov, Victor G.; Yakubenko, Artyom A.; Verkhov, Valeriy A.; Antonov, Alexander S.

doi:10.1021/acs.organomet.2c00115

Cited by 4 publications

(4 citation statements)

References 61 publications

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“…By the beginning of our work, the 2,3,6,7 derivatives of DMAN, required to study this question, were unknown. The difficulty of obtaining them lies in the inertness of positions 3 and 6 in DMAN to any functionalization except for borylation and metalation with superbases . To solve this problem, we tried to carry out directed ortho metalation of DMAN derivatives 2–4 containing OMe, NMe 2 , and SMe groups at positions 2 and 7 (difficulties associated with metalation of DMAN itself are reflected in refs and ).…”

Section: Resultsmentioning

confidence: 99%

Organometallic Synthesis of 2,3,6,7-Tetrasubstituted 1,8-Bis(dimethylamino)naphthalenes for Investigation of the Double Buttressing Effect in Proton Sponges

et al. 2022

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The lithiation of 2,7-disubstituted derivatives of 1,8bis(dimethylamino)naphthalene (DMAN, proton sponge) bearing potentially ortho-directing OMe, NMe 2 , and SMe groups was studied. It has been shown that OMe groups facilitate selective dual βlithiation of the naphthalene moiety while the 2(7)-NMe 2 groups allow only monolithiation presumably due to the decreased acidity of the ring C−H bonds and conformational immobilization after coordination to the lithium atom. In contrast, the SMe groups provided no ring lithiation and underwent deprotonation of their methyl fragment. The first representatives of previously unknown 2,3,6,7-tetrasubstituted DMANs have been synthesized in good yield after treatment of 2,7-dimethoxy-3,6-dilithio DMAN with the appropriate electrophiles (MeI, Me 2 S 2 , Me 3 SiCl, DMF, etc.). Because the exceedingly high basicity of 2,7-dimethoxy DMAN is commonly attributed to the so-called "buttressing effect" (BE), the availability of 2,3,6,7-tetrasubstituted species provided the first opportunity to study the double BE version. Using X-ray diffraction and basicity measurements, we showed that due to the high conformational mobility of the methoxy groups, the most striking manifestations of double BE are the strong planarization of peri-NMe 2 groups and a significant decrease in basicity, while the length and the other properties of the intramolecular NHN hydrogen bond in the corresponding protonated species undergo minor changes.

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Section: Resultsmentioning

confidence: 99%

Organometallic Synthesis of 2,3,6,7-Tetrasubstituted 1,8-Bis(dimethylamino)naphthalenes for Investigation of the Double Buttressing Effect in Proton Sponges

et al. 2022

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“…peri -Dilithionaphthalenes provide a rigid backbone perfectly suitable for the construction of a heterocyclic core. This feature was successfully utilized for the synthesis of fused 1,2-diphospholanes, , 1,2-dithiolane, , and 1,2,5-oxadiborolanes. , At the same time, they have never been studied as substrates for the preparation of six-membered nitrogen heterocycles. To fill this disappointing gap in the chemistry of azines, here we present a convenient transformation of peri -dilithionaphthalenes into benzo[ de ]isoquinolines, quite rare heterocyclic systems. , …”

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confidence: 99%

Spontaneous Cyclization of peri-Diiminonaphthalenes Leading to the Formation of Benzo[de]isoquinolines and Stable Benzo[de]isoquinoliniums

et al. 2023

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The interaction of peri-dilithionaphthalenes with organic cyanides was studied. Instead of the expected peri-diimines, the reaction leads to the formation of three types of benzo[de]isoquinolines. Treatment of unsubstituted 1,8-dilithionaphthalene with aromatic nitriles results in the formation of 1-amino-1,3-diaryl-1H-benzo[de]isoquinolines. In contrast, 4,5-dilithio-1,8-bis(dimethylamino)naphthalene gives an aromatic isoquinolonium cation via elimination of ammonia under the same condition. Upon treatment with tert-butylcyanide, both dilithionaphthalenes undergo a transformation to 1-amino-3,4-di-tert-butyl-4H-benzo[de]isoquinolines. The observed reactivity was supported by quantum chemical calculations.

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“…There are also substituted 1,8-dilithionaphthalenes such as 5,6-dilithioacenaphthalene 26 and 4,5-lithio-1,8-bis(dimethylamino)naphthalene 27 (Scheme ). 27 was known as a “proton sponge” and could be employed to synthesize the corresponding boron-containing heterocycles. , In addition to lithium–bromine exchange, 1,8-dilithionaphthalene derivatives could also be prepared via abstracting a proton from 1-lithionaphthalenes with n BuLi . Generally, the assistance of TMEDA as a coordinating ligand was required.…”

Section: 2- and 13-dicarbanion Compoundsmentioning

confidence: 99%

Dicarbanion Compounds: The Bridge between Organometallic Reagents and Mononuclear Heterocycles

Chai

Zhang

2022

Organometallics

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Dicarbanion compounds, namely organo-bi-metallics in which two metal atoms are separated by all-carbon backbones, are of great importance in organometallic chemistry for not only the interest in the structure but also the wide application in synthesis, especially of mononuclear heterocycles. The synthetic methods and reactivities of dicarbanion compounds highly depend on the type of metals as well as the structure of backbones. For metal types, while there are examples of other metals, lithium and magnesium play important roles in the chemistry of dicarbanion compounds. For the backbone structure, different unsaturated bonds in the backbones result in different rigidities and orientations of carbon−metal bonds and thus have a great impact on the reactivity of dicarbanion compounds. Herein, a general review of the preparation, structure, and reactivity of dicarbanion compounds with different metals and backbones are presented, mainly focusing on the dicarbanion compounds that have been or may potentially be employed in mononuclear heterocycle synthesis. Heterocycles mentioned in this review are mostly metallacycles because of the limitation of synthetic methods.

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Organoboron Derivatives of 1,8-Bis(dimethylamino)naphthalene: Synthesis, Structure, Stability, and Reactivity

Cited by 4 publications

References 61 publications

Organometallic Synthesis of 2,3,6,7-Tetrasubstituted 1,8-Bis(dimethylamino)naphthalenes for Investigation of the Double Buttressing Effect in Proton Sponges

Organometallic Synthesis of 2,3,6,7-Tetrasubstituted 1,8-Bis(dimethylamino)naphthalenes for Investigation of the Double Buttressing Effect in Proton Sponges

Spontaneous Cyclization of peri-Diiminonaphthalenes Leading to the Formation of Benzo[de]isoquinolines and Stable Benzo[de]isoquinoliniums

Dicarbanion Compounds: The Bridge between Organometallic Reagents and Mononuclear Heterocycles

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