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1.
Conclusions
3JHH SSCC values and the13C chemical shifts of derivatives of 3-borabicyclo[3.3.1]nonane with a three-coordinated boron atom have a flattened double-chair conformation. The derivatives with a four-coordinated boron atom and a substituent at the 7 position have predominantly the chair-boat conformation, and the cyclohexane ring has the boat form; the the exceptions are the compounds with an internal donor-acceptor bond between boron and the 7 substituent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 341–352, February, 1981. 相似文献
2.
L.S. Vasilyev V.V. Veselovskii M.I. Struchkova B.M. Mikhailov 《Journal of organometallic chemistry》1982,226(2):115-128
Bromination of 3-isopropyl-7-methyl- and 3-isopropyl-7-bromomethyl-3-borabicyclo[3.3.1]nonane leads to corresponding 3-(2-bromo-2-propyl) derivatives, which, on treatment with alcohols or pyridine as well as on heating, undergo the Matteson-Pasto rearrangement to convert into 3-X-4,4,8-trimethyl- and 3-X-4,4-dimethyl-8-bromomethyl-3-borabicyclo[4.3.1]decane (X = Br, OR). Interaction between triethylamine and 3-(2-bromo-2-propyl)-7-methyl-3-borabicyclo[3.3.1]nonane is accompanied by dehydrobromination leading to 3-isopropenyl-7-methyl-3-borabicyclo[3.3.1]nonane. Carbonylation of 3,4,4,8-tetramethyl-3-borabicyclo[4.3.1]decane at 140°C is accompanied by migration of two alkyl groups from the boron to the carbon atom, and subsequent oxidation with H2O2 produces 1-(2-hydroxy-2-methyl-1-propyl)-3-acetonyl-5-methyl-cyclohexane. Under more forcing conditions (180-195°C), the third alkyl group also migrates to give, after oxidation, a mixture of isomeric 3,4,4,8-tetramethylbicyclo[4.3.1]decan-3-ols. 3-n-Butoxy-4,4-dimethyl-8-bromomethyl-3-borabicyclo[4.3.1]decane, on treatment with Lì, undergoes cyclization to afford 4,4-dimethyl-3-borahomoadamantane, carbonylation and subsequent oxidation of which gave 4,4-dimethylhomoadamantan-3-ol. 相似文献
3.
J.A. Peters J M.A. Baas B. Van De Graaf J.M. Van Der Toorn H. Van Bekkum 《Tetrahedron》1978,34(22):3313-3323
ΔG-Values for conformational equilibria in 3,7-substituted bicyclo[3.3.1]nonanes have been obtained by means of epimerisation experiments (cc α bc) and by variable temperature 13C NMR (bc α bb). The results of these experiments fit well with those of molecular mechanics using the Schleyer force field. In bicyclo[3.3.1]nonane and 3β-substituted derivatives the cc conformation predominates; however, the bulky 3β-substituent t-butyl, is found to have a destabilizing effect. A 3α-substituent forces the substituted wing into the boat conformation. For the 3α,7α-substituted derivatives the conformational preferences depend on the size of the substituents: for 3α-methyl-7α-t-butylbicyclo[3.3.1]nonane the cb and t-bb conformers are of approximately equal enthalpy. The geometries, obtained by the calculations, show that the conformers of bicyclo[3.3.1]nonane (cc, bc and t-bb) are all distinctly flattened. The boat wings of bc conformers are not twisted to any extent. The t-bb is the most stable bb conformation. The influence of substitution at positions 3 or 7 is discussed in detail; in general, a bulky substituent such as t-butyl, affects the geometry of both wings of the ring system. The calculated geometries are in good agreement with the conclusions of previous 1H NMR investigations. 相似文献
4.
The 13C NMR spectra of a series of 3,7-substituted bicyclo[3.3.1]nonane derivatives are examined. Taken into account substituent influences, the 13C chemical shifts appear to be diagnostic for the conformation of the bicyclo[3.3.1]nonane derivative. 相似文献
5.
Mikhail E. Gurskii Ilya D. Gridnev Yuri N. Bubnov Andrew Pelter Paul Rademacher 《Journal of organometallic chemistry》1999,590(2):227
3-Methoxy-7α-phenyl-1,5-dimethyl-3-borabicyclo[3.3.1]nonane 5 in solution at room temperature exists in the double chair conformation, as shown by NMR studies. Increasing the temperature leads to an increase in the population of the chair–boat conformation. At decreased temperature hindered rotation around the B---O bond is observed for 5. Dissolving 5 in deuteropyridine leads to the reversible formation of complex 6, which exists in the chair–boat conformation. The chair–boat conformation is also the most stable one for chelate compound 7 with a tetracoordinated boron atom. 相似文献
6.
3-Methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-α(β)-ols have been synthesized and studied by ir, 1H and 13C nmr spectroscopy. In deuteriochloroform and perdeuteriobenzene solutions, these compounds adopt a flattened chair-chair conformation in which the cyclohexane ring is more flattened. From the 1H and 13C nmr data, several stereoelectronic effects have been deduced. The complete and unambiguous assignment of all protons of the 3-azabicyclo[3.3.1]nonane system, not described up to date, has been carried out. 相似文献
7.
N. Yu. Kuznetsov Z. A. Starikova B. B. Averkiev Yu. N. Bubnov 《Russian Chemical Bulletin》2005,54(3):678-683
A method was developed for the synthesis of 6,7-benzo-3-borabicyclo[3.3.1]nonane and 6,7-benzo-3-azabicyclo[3.3.1]nonane derivatives based on intramolecular cyclization of 2-allylphenyl(diallyl)borane. Intramolecular arylboration of the double bond in 1,5-diallyl-2,3-benzo-1-boracyclohexane was carried out for the first time. Conventional oxidation (H2O2-OH−) of 6,7-benzo-3-methoxy-3-borabicyclo[3.3.1]nonane afforded cis-1,3-di(hydroxymethyl) tetralin. The structure of the latter was established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 668–672, March, 2005. 相似文献
8.
M. E. Gurskii K. A. Lyssenko A. L. Karionova P. A. Belyakov T. V. Potapova M. Yu. Antipin Yu. N. Bubnov 《Russian Chemical Bulletin》2004,53(9):1963-1977
The conformational equilibrium in solution was examined by NMR spectroscopy for a series of 7-phenyl-3-borabicyclo[3.3.1]nonane derivatives containing various substituents at the boron atom. The structures of these derivatives were studied in the crystalline state (X-ray diffraction analysis) and by quantum-chemical calculations (B3Pw91/6-31G*). The B...Ph transannular interactions corresponding to charge transfer from the system of the phenyl group to the vacant p-orbital of the B atom were demonstrated to be responsible for unique stability of the chair-chair conformation of these derivatives.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1884–1896, September, 2004. 相似文献
9.
J.A. Peters P.E.J. Peters-Van Cranenburgh J.M. Van Der Toorn Th.M. Wortel H. Van Bekkum 《Tetrahedron》1978,34(14):2217-2222
The conformation of 3-oxabicyclo[3,3.1]nonane and of some of its 7α- and 7β-alkyl substituted derivatives has been studied with the use of 13C and 1H NMR spectroscopy. A comparison is made with the carbocyclic analogues; it turns out that the replacement of the 3-methylene group by oxygen has no substantial influence on the conformational preferences. With the aid of 3JHH coupling constants it is shown that the geometry of the cyclohexane rings is about the same as in the corresponding carbocyclic compounds. The results of calculations on the lanthanide induced shifts indicate that the tetrahydropyran ring is not flattened but probably somewhat puckered. The calculated location of Eu(III) in complexes of Eu(dpm)3 with the 3-oxabicyclo [3.3.1]nonanes is compared with that in the complexes of the related compounds 2-oxaadamantane and 4-methyltetrahydropyran. The data indicate that the lanthanide ion coordinates “axially” to the latter compound. 相似文献
10.
M. E. Gurskii P. A. Belyakov K. A. Lyssenko A. L. Semenova Yu. N. Bubnov 《Russian Chemical Bulletin》2014,63(2):480-486
2D 1H-1H EXSY NMR spectroscopy show that the free energy of activation ΔG ≠ in six 3-allyl-3-borabicyclo[3.3.1]nonane derivatives is significantly higher (72–86 kJ mol?1) than that in typical allylboranes (48–66 kJ mol?1). For the first member of the series, viz., 3-allyl-3-borabicyclo[3.3.1]nonane, the activation parameters of the permanent allylic rearrangement were also determined (ΔH ≠ = 82.7±3.4 kJ mol?1, ΔS ≠ = ?11.8±10.3 J mol?1 K?1, E A = 85.5±3.4 kJ mol?1, lnA = 29.2±1.2). 相似文献
11.
Facile and convenient synthesis of B-amino-9-borabicyclo[3.3.1]nonanes. Aminoboration of lsocyanates
Bakthan Singaram 《Heteroatom Chemistry》1992,3(3):245-249
The reaction of 9-borabicyclo[3.3.1]nonane (9-BBN) with aliphatic and aromatic primary and secondary amines in tetrahydrofuran (THF) at 65°C proceeds rapidly and quantitatively with evolution of hydrogen and the formation of the corresponding B-amino-9-borabicyclo[3.3.1] nonane (B-amino-9-BBN). Simple evaporation of THF from the reaction mixture gives the B-amino-9-BBN derivatives in high yield and purity. These B-amino-9-BBN derivatives are reactive towards alkyl and aryl isocyanates. Consequently, the aminoboration of various isocyanates has been studied using B-phenylamino-9-BBN. Thus, two equivalents of isocyanates react with one equivalent of B-phenylamino-9-BBN to afford, following the hydrolysis of the intermediate with ethanolamine, N, N'-disubstituted-N -(phenylamido)-ureas in excellent yields. A plausible mechanism for this aminoboration reaction of isocyanates is also presented. 相似文献
12.
A. Zschunke C. Mügge M. v. Lwis F. Krech L. Weber H. Schumann H. G. Stammler 《无机化学与普通化学杂志》1992,610(4):127-134
γ-Anti Effect in 1-Phosphabicyclo[3.3.1]nonane Derivatives with Substituents at Phosphorus. Synthesis and Structure of Pentacarbonyl(1-phosphabicyclo[3.3.1]nonane) Chromium In 1-phosphabicyclo[3.3.1]nonane derivatives of the composition C8H15P(X) the CC-conformation always dominates. Changes in the chemical shifts of the bridge-head carbon atom C(5) in the 13C-NMR spectrum are only originated by the electronic influence of the substituent X at the phosphorus centre. Based on a homogeneous interpretation of the electronic interactions and with regard to Pearsons's definition of electronegativity the electronegativities of substituents at the phosphorus atom X = Cr(CO)5, Fe(CO)4, and Ni(CO)3 are estimated. These groups are placed in antiperiplanar orientation to the carbon atom C(5). The molecular structure of (1-phosphabicyclo[3.3.1]-nonane) Cr(CO)5 3 was elucidated by X-ray diffraction analysis. The molecule features the 1-phosphabicyclononane ligand in the CC-conformation, which has a nearly undistorted Cr(CO)5 unit coordinated to the phosphorus atom (d Cr P = 2.368(1) Å). 相似文献
13.
The conformation of bicyclo[3.3.1]nonane-3α,7α-dicarboxylic acid and its dimethyl ester has been studied by comparing 1H NMR and 13C NMR spectra of these compounds with those of some model 3,7-disubstituted bicyclo[3.3.1]nonanes, fixed in a single conformation by the use of adamantane as an integrated holding group or by means of suitable substitution. It is shown that the dicarboxylic acid and its dimethyl ester exist predominantly as two rapidly interconverting (identical) chair-boat conformations with distinctly flattened rings; the population of the double-boat conformation appears to be very small. 相似文献
14.
《Tetrahedron》1988,44(17):5597-5604
(R)- and (S)-[2-2H]glycine of high chiral purity were synthesized in large quantities in ≈ 40% overall yield from readily available starting materials via a totally chemical procedure. Reduction of either [1-2H]-furfural or [1-2H]-4-methoxybenzaldehyde with either (+) or (-)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane gave chiral arylmethyl alcohols which were converted into their respective phthaloyl amino derivatives of the opposite configuration at the methylene carbon via the Mitsunobu reaction. The aromatic groups were oxidatively unmasked to give their corresponding glycine derivatives by either ozone or ruthenium tetraoxide oxidation. 相似文献
15.
Conclusions Some B-derivatives (alkoxy, alkylmercapto, amino) of 3-borabicyclo[3.3.1]-6-nonene and 3-borabicyclo[3.3.1]nonane were obtained and studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, N. 4, pp. 824–827, April, 1968. 相似文献
16.
M. E. Gurskii S. Yu. Erdyakov T. V. Potapova Yu. N. Bubnov 《Russian Chemical Bulletin》2008,57(4):802-814
The review summarizes our data on the synthesis of selected allylic, bicyclic, and highly strained cage boranes, investigations
of their physicochemical properties, and applications of these compounds. Procedures for the construction of boron polyhedral
systems, transformations of 1-boraadamantane compounds into 1-hydroxyadamantanes and 1-azaadamantanes, and the synthesis of
chiral derivatives of 1-boraadamantane and 3-borabicyclo[3.3.1]nonane are considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 788–800, April, 2008. 相似文献
17.
The stereochemistry of syn and anti-forms of bridged bicyclo[3.n.1]-2-ene, tricyclo[7.n.1.0]-2-ene (n=1-3) and bicyclo[4.3.1]dec-7-ene derivatives can be assigned from the 13C chemical shift difference of the double bond. Both syn-9-R-bicyclo[3.3.1]non-2-enes and syn-13-R-tricyclo[7.3.1.02,7]tridec-2(7)-enes have a large shielding difference between sp2 carbons, while the corresponding anti-forms have a smaller one. In contrast, 8-R-bicyclo[3.2.1]oct-2-enes and 12-R-tricyclo[7.2.1.02,7]dodec-2(7)-enes have an inverse correlation. The reason of this specificity is the influence of the γ-gauche effect on the chemical shift of C(2) atom. The GIAO theory has been applied to investigate the 13C chemical shifts. The conformational equilibrium in the formamide group of 13-formylamino-tricyclo[7.3.1.02,7]tridec-2(7)-enes has been studied. 相似文献
18.
α-Bromomethyl-α,β-unsaturated ketones can be prepared easily by the successive addition of α,β-unsaturated ketones and then aldehydes to B-bromo-9-borabicyclo[3.3.1]nonane. 相似文献
19.
V. S. Bogdanov M. G. Kurella L. G. Vorontsova N. E. Agafonov G. Ya. Kondrat'eva V. I. Andrianov 《Russian Chemical Bulletin》1988,37(5):892-896
Conclusion
13C and1H NMR spectroscopy was used to determine the structures of 2-aryl-1,3-dibenzoyl-1, 3-diazabicyclo[3.3.1]nonanes and 2-aryl-1-benzyl-3-benzoyl-1,3-diazabicyclo[3.3.1]nonane. These compounds were found to exist predominantly in the boat-chair conformation (boat for the diaza ring), while the 2-aryl substituents occupy the exo or endo position.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1023–1028, May, 1988. 相似文献
20.
Extraordinary stereoselectivity, approaching 100%, has been reported in the reductions of d-benzaldehydes by B-isopinocampheyl-9-borabicyclo[3.3.1]nonane (Alpine-Borane). This is likely because of the extreme size disparity of groups on either side of the carbonyl. Here, we present a structure–reactivity study whereby the reductions of variably substituted d-benzaldehydes are explored using highly sensitive measures for enantiomeric excess and relative reactivity. These results are compared to the relative rates predicted from density functional calculations. The results indicate that 2,6-disubstitution adversely affects the stereoselectivity by means of a non-selective reduction via the dehydroboration product of Alpine-Borane, 9-borabicyclo[3.3.1]nonane. 相似文献