Tetracyclopropylmethane: A Unique Hydrocarbon with S4 Symmetry

Kozhushkov, Sergei I.; Kostikov, R. R.; Molchanov, A. P.; Boese, Roland; Benet‐Buchholz, Jordi; Schreiner, Peter R.; Rinderspacher, Christopher; Ghiviriga, Ion; Meijere, Armin de

doi:10.1002/1521-3773(20010105)40:1<180::aid-anie180>3.0.co;2-k

Cited by 24 publications

(4 citation statements)

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“…Ready crystallisation of both diastereomers allowed the determination of the solidstate structure. Rac-2 with D 2 symmetry crystallised in a non-chiral space group (P-1, Figure 3) differently from (S,S) ax -2 (I 2 1 2 1 2 1 ; [3]), while meso-2 revealed a nearly perfect S 4 symmetry in the solid state (Figure 4), a point group rarely found in organic molecules [22][23][24][25][26][27][28]). Ellipsoids were drawn at the 50% probability level.…”

Section: Comparison Of Solid-state Structures Of Meso-2 and Rac-2 (Ra...mentioning

confidence: 99%

Racemic and Meso Crystal Structures of an Axial-Chiral Spirobi-(dinaphthoazepin)ium Salt: Emergence of an S4-Symmetric Molecule

et al. 2021

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To date, only a few instances of S4-symmetric organic molecules exist. In principle, spirobi-(dinaphthoazepin)ium cations can achieve this highly symmetric point group. Heating racemic 2,2′-bis(bromomethyl)-1,1′binaphthyl with aqueous ammonia afforded a mixture of rac- and meso-3,3′,5,5′-tetrahydro-4,4′-spirobi[dinaphtho[2,1-c:1′,2′-e]azepin]-4-ium bromide which was separated by fractional crystallisation. Both stereoisomers were characterised spectroscopically, and their crystal structures were determined and compared. The rac crystal structure differs significantly from the known enantiopure one. The meso molecules display a near-perfect S4 symmetry. Upon treatment with KOtBu, both isomers undergo Stevens rearrangement.

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Section: Comparison Of Solid-state Structures Of Meso-2 and Rac-2 (Ra...mentioning

confidence: 99%

Racemic and Meso Crystal Structures of an Axial-Chiral Spirobi-(dinaphthoazepin)ium Salt: Emergence of an S4-Symmetric Molecule

et al. 2021

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“…Eventually, 496 was prepared by repeated addition of Pd(OAc) 2 to a solution of dicyclopropyldivinylmethane (495) and diazomethane in ether (Scheme 79). 342,343 According to an X-ray diffraction study, the hydrocarbon 496 adopts an S 4 -symmetrical conformation in the crystal. 342 Catalytic hydrogenation of 496 furnished the previously unknown tetraisopropylmethane (497) in quantitative yield (Scheme 79).…”

Section: Oligocyclopropyl-substituted Alkanes Alkenes and Alkynesmentioning

confidence: 99%

“…342,343 According to an X-ray diffraction study, the hydrocarbon 496 adopts an S 4 -symmetrical conformation in the crystal. 342 Catalytic hydrogenation of 496 furnished the previously unknown tetraisopropylmethane (497) in quantitative yield (Scheme 79). This even more sterically crowded hydrocarbon assumes a D 2d -symmetric conformation, which, according to computations, is not much different geometrically and energetically from the corresponding S 4 -symmetric conformation.…”

Section: Oligocyclopropyl-substituted Alkanes Alkenes and Alkynesmentioning

confidence: 99%

“…This even more sterically crowded hydrocarbon assumes a D 2d -symmetric conformation, which, according to computations, is not much different geometrically and energetically from the corresponding S 4 -symmetric conformation. 342 The dynamics of the conformational changes of these highly congested hydrocarbons have been studied by NMR spectroscopy. 343 Tetrakis(cyclopropylmethyl)methane (498) was synthesized along the same lines as tetracyclopropylmethane (496).…”

Section: Oligocyclopropyl-substituted Alkanes Alkenes and Alkynesmentioning

confidence: 99%

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