Investigations into the preparation of sila-β-diketones via 2-trimethylsilyl-1,3-dithianes: structural characterization of a second polymorph of bis(2,2,6,6-tetramethyl-2-sila-3,5-heptanedionato)copper(II)

Claessen, Rolf U.; Kornilov, A. M.; Banger, Kulbinder K.; Ngo, Silvana C.; Higashiya, Seiichiro; Wells, Christopher; Dikarev, Evgeny V.; Toscano, Paul J.; Welch, John T.

doi:10.1016/j.jorganchem.2003.09.032

Cited by 7 publications

(2 citation statements)

References 40 publications

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“…X-ray structures of bis-dithianes such as 8-(OAc) 2 have been extensively studied. [99][100][101][102] The crystallographic data for the four structures are listed in Table 2.…”

Section: 5-dimethoxy B-diketones With Meso-alkylationmentioning

confidence: 99%

Synthesis of diverse acyclic precursors to pyrroles for studies of prebiotic routes to tetrapyrrole macrocycles

et al. 2016

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“…X-ray structures of bis-dithianes such as 8-(OAc) 2 have been extensively studied. [99][100][101][102] The crystallographic data for the four structures are listed in Table 2.…”

Section: 5-dimethoxy B-diketones With Meso-alkylationmentioning

confidence: 99%

Synthesis of diverse acyclic precursors to pyrroles for studies of prebiotic routes to tetrapyrrole macrocycles

et al. 2016

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“…Based on the experimental ( 1 H NMR) and theoretical vicinal coupling constants the ΔG 0 values were determined of the methyl group at the ring C 5 atom. The reasons for the distinctions between the values of this parameter from the ΔG 0 , obtained by energy minimizations of the equatorial and axial chair conformers are discussed.The interest in substituted 1,3-dithianes are due both to the peculiarities of their structure [1][2][3][4][5][6][7][8][9][10][11] and to their use as reagents in fine organic synthesis [12][13][14][15][16][17][18][19]. Earlier using 1 H and 13 C NMR spectroscopy it has been shown that the main minimum on the potential energy surface (PES) of 5-alkyl-1,3-dithianes is the equatorial chair conformer (C e ) [2, 3, 5-9].…”

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Conformational analysis of 5-methyl- and 2,2,5-trimethyl-1,3-dithianes

Кузнецов

2012

Russ J Gen Chem

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Conformational isomerization of 5-methyl-and 2,2,5-trimethyl-1,3-dithianes was studied using quantum-chemical HF/6-31G(d), HF/pVDZ, and PBE/3z approximations. The potential energy surface of molecules of both compounds is shown to contain the main minimum corresponding to the equatorial chair conformer C-5e. The calculated potential barriers of the conformational isomerization were found. Based on the experimental ( 1 H NMR) and theoretical vicinal coupling constants the ΔG 0 values were determined of the methyl group at the ring C 5 atom. The reasons for the distinctions between the values of this parameter from the ΔG 0 , obtained by energy minimizations of the equatorial and axial chair conformers are discussed.The interest in substituted 1,3-dithianes are due both to the peculiarities of their structure [1][2][3][4][5][6][7][8][9][10][11] and to their use as reagents in fine organic synthesis [12][13][14][15][16][17][18][19]. Earlier using 1 H and 13 C NMR spectroscopy it has been shown that the main minimum on the potential energy surface (PES) of 5-alkyl-1,3-dithianes is the equatorial chair conformer (C e ) [2, 3, 5-9]. Computer simulation applied to the conformational analysis of unsubstituted 1,3-dithiane has revealed the main conformer, the chair (C), and the local minima, 1,4-twist (1,4-T) and 2,5-twist (2,5-T), as well as transition states (TS): the semi-chair, symmetric boat and asymmetric boat conformations [20,21]. In this paper conformational analysis is performed of the molecules of 5-methyl-(I) and 2,2,5-trimethyl-1,3-dithianes (II) using ab initio quantum chemical approximations HF/6-31G(d), HF/pVDZ, and PBE/3z within the HyperChem [22] and PRIRODA [23] software packages.compounds I and II contains five minima: the equatorial chair and axial chair conformers (C e , C a ), as well as flexible conformers, 1,4-T and two enantiomeric forms of 2,5-T. The overall picture of the conformational transitions in this case corresponds to a trigonal bipyramid.Note that all the used approximations show only one of the two possible 1,4-T forms, with pseudoequatorial methyl group at the C 5 atom of the ring. In the course of the geometry optimization and energy minimization the alternative conformer is irreversibly converted into 2,5-T form.Analysis of the calculated parameters of the conformational equilibria of studied 1,3-dithianes (Table 1) shows that the difference in the energy of C e and C a forms (ΔH) is 1.2-1.5 kcal mol -1 , except for the case of HF/pVDZ approximation. Accordingly, the value of ΔG 0 for the C e ↔ C a equilibrium is equal to 1.3-1.4 kcal mol -1 (PBE/3z). However, the calculated value of ΔH for similar conformers of 5-methyl-1,3-dioxane in the framework of the HF/6-31G(d) does not exceed 0.6 kcal mol -1 [25] . The large value of this parameter for compounds I and II is difficult to explain by steric interactions of the axial methyl group at the C 5 atom with the heteroatomic ring fragment, because an increase in the C-S bond length compared with C-O, should, conversely, reduce the ΔH a...

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Synthesis of Metal Enolato Complexes

Vicente

2010

Patai's Chemistry of Functional Groups

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Introduction Synthesis from Ketones, Aldehydes and Esters Synthesis from Ketenes, Isocyanates and Acyl Halides Synthesis from Carbon Monoxide and Carbonyl Complexes Synthesis via Cleavage of Ethers and Related Compounds Synthesis from Oxo, Hydroxo or Alkoxo Complexes Oxygenation Reactions Miscellaneous Reactions Acknowledgments

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Investigations into the preparation of sila-β-diketones via 2-trimethylsilyl-1,3-dithianes: structural characterization of a second polymorph of bis(2,2,6,6-tetramethyl-2-sila-3,5-heptanedionato)copper(II)

Cited by 7 publications

References 40 publications

Synthesis of diverse acyclic precursors to pyrroles for studies of prebiotic routes to tetrapyrrole macrocycles

Synthesis of diverse acyclic precursors to pyrroles for studies of prebiotic routes to tetrapyrrole macrocycles

Conformational analysis of 5-methyl- and 2,2,5-trimethyl-1,3-dithianes

Synthesis of Metal Enolato Complexes

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