Darstellung von Achtgliedrigen Bor-Heterocyclen Durch Kondensation

Gerwarth, Ulrich W.; Weber, W.

doi:10.1080/00945717508055934

Cited by 8 publications

(2 citation statements)

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“…The size and the electronic effects of the substituents markedly influence the magnitude of N-B coordination. In accordance with these findings, replacement of the ring nitrogen atom by oxygen or sulphur led to fairly unstable non-crystalline compounds without any detectable transannular bonding (7).…”

Section: Introductionsupporting

confidence: 70%

“…Other boracyclooctanes having trivalent boron and nitrogen atoms in the 1-and 5-positions are prone to transannular N+B coordination, forming bicyclo[3.3.0]octanes as shown for several different types of boron heterocycles (3,25,26). Structural stabilization, weak in eight-membered cyclic boronates with little or no transannular coordination (5,7), is achieved in 3 by quaternization of both boron and nitrogen resulting in a zwitterionic salt structure. Dissociative and reassociative processes in solutions of cyclic boronates of bis(2-hydroxyethy1)amines (9 o 10) have been monitored by dynamic nmr spectroscopy (5).…”

Section: Introductionmentioning

confidence: 99%

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Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

Kliegel¹,

Rettig²,

Trotter³

1988

Can. J. Chem.

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. Can. J. Chem. 66, 109 1 (1988). Details of the preparation and structure of the title compound are given. Crystals of 6,6-diethyl-2,2-diphen 1-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate are orthorhombic, a = 7.0322(2), b = 16.3505(7), c = 16.8164(4) 1, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.045 and R,, = 0.050 for 2013 reflections with I 2 3 4 4 . The monocyclic eight-membered B, N-betaine is the first to be structurally characterized. The eight-membered chelate ring has a conformation intermediate between the S4 and boat-boat forms which is probably stabilized by transannular C-H...O interactions. The average libration-corrected 0-B and B-C bond lengths of 1.500 and 1.639 A are, respectively, the shortest and longest yet observed for an 0,O-chelate of diphenylboron.WOLFGANG KLIEGEL, STEVEN J. RETTIG et JAMES TROTTER. Can. J. Chem. 66, 1091Chem. 66, (1988. On rapporte les dCtails de la priparation et de la ditermination de la structure du compost mentionne dans le titre. Les cristaux du monohydrate du diCthyl-6,6 diphknyl-2,2 dioxa-1,3 azonia-6 borata-2 cyclooctane sont orthorhombiques avec a = 7,0322(2), b = 16,3505(7) et c = 16,8164(4) A, Z = 4 et groupe d'espace P212121. On a rCsolu la structure par des mkthodes directes et on l'a affinCe par la mCthode des moindres carrCs (matrice entibre) jusqu'a des valeurs de R = 0,045 et R, = 0,050 pour 2013 rkflexions avec I 2 3 4 4 . La B,N-bCtai'ne monocyclique h huit chainons est la premikre a avoir Ct C caracttriste du point de vue de sa structure. Le chtlate cyclique a huit chaions possbde une conformation qui est intermtdiaire entre les formes S4 [Traduit par la revue] Introduction 1,3-Dioxa-6-aza-2-boracyclooctanes 1 are known to undergo intramolecular (transannular) N+B coordination to give very stable bicyclo[3.3 .O]octane ring systems 2, confirmed by chemical and physical investigations (1-6). Generally the extent of the N+B interaction depends on the nitrogen and boron substitution as well as on the conformational conditions. The size and the electronic effects of the substituents markedly influence the magnitude of N-B coordination. In accordance with these findings, replacement of the ring nitrogen atom by oxygen or sulphur led to fairly unstable non-crystalline compounds without any detectable transannular bonding (7).A cyclooctane system without a transannular N 4 B interaction should be realized by quaternization of both the tertiary amine and boronate groups of 1. Direct N-alkylation and B-arylation of the known (8) compound 112 seemed disadvantageous, so the synthesis of 3 was carried out by N-alkylation of 2-diethylaminoethanol 6 via the addition of oxirane (ethylene oxide) and subsequent trapping of the zwitterionic intermediate 4 as the diphenylboron chelate 3. The symmetrical cyclic B,N-betaine structure 3 has been postulated in a preliminary report (9) on the basis of 'H nrnr data which suggest magnetically equivalent ethylene moieties with...

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Section: Introductionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

Kliegel¹,

Rettig²,

Trotter³

1988

Can. J. Chem.

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Bench‐Stable Sulfoxide‐Based Boronates: Preparation and Application in a Tandem Suzuki Reaction

2018

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A set of novel aromatic and heteroaromatic bench‐stable sulfoxide‐based boronates was prepared. The structure of the boronates was established by means of X‐ray crystallography, and the prepared boronates were successively used in Suzuki cross‐coupling reactions under different conditions. We also developed a tandem Suzuki reaction so that a base is generated during the nucleophilic addition of Grignard reagents to 4‐bromobenzaldehyde. The formed intermediates were smoothly coupled with the prepared boronates and the boronic acids under external base‐free conditions.magnified image

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ChemInform Abstract: Darstellung von achtgliedrigen Bor‐Heterocyclen durch Kondensation.

Gerwarth¹,

Weber²

1976

Chemischer Informationsdienst

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Darstellung von Achtgliedrigen Bor-Heterocyclen Durch Kondensation

Cited by 8 publications

References 5 publications

Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

Bench‐Stable Sulfoxide‐Based Boronates: Preparation and Application in a Tandem Suzuki Reaction

ChemInform Abstract: Darstellung von achtgliedrigen Bor‐Heterocyclen durch Kondensation.

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