Deuterium and the octant rule for ketones. Syntheses and circular dichroism data of chiral 4-deuterioadamantan-2-ones

Numan, H.; Wynberg, Hans

doi:10.1021/jo00405a030

Cited by 25 publications

(3 citation statements)

References 10 publications

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“…(d, 1 C), 33.8 (s, 1 C), 32.0 (t, I C), 31.6 (t, 1 C), 29.1 (t, 1 C), 28.7 (9, 1 C), 28.4 (d, I C), 27.1 (t, 1 C), and 26.6 (4, 1 C); m/z 177 ( M + , loo%), 162 (43), 108 (22), 107 (33), 94 (36), 93 (29), 91 (lo), 81 (16), 80 (18), 79 (34), 77 ( I I ) , 67 (18), 57 (12), 56 (13), 55 (Il), 53 (lo), 43 (12), and 41 (34).…”

Section: -Endo-dideuterioazidometh~~~icyclo[331 Jnon-6-ene ['H2]-@mentioning

confidence: 99%

Synthesis and acidolysis of 3-endo-azidomethyl- and 3-endo-azidobicyclo[3.3.1]non-6-enes. A novel synthesis of 4-azahomoadamant-4-enes

Sasaki¹,

Eguchi²,

Toi³

et al. 1983

J. Chem. Soc., Perkin Trans. 1

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The acidolysis of 3-endo-azidomethylbicyclo[3.3.1 lnon-6-ene (3) with methanesulphonic acid gave 4-azahomoadamant-4-ene (5) which was also produced from 3-endohydroxymethylbicyclo[3.3.1] non-6-ene (6) on treatment with NaN,-MeS0,H.The formation of (5) was rationalized by a x route cyclization followed by acidolytic ring expansion of intermediate azides on the basis of acidolysis of dideuterioderivatives. The above route was extended to synthesis of 2,2-(1 6) and 7,7-dimethyl-4-azahomoadamant-4-enes (1 7). The acidolysis of 3-endo-azidobicyclo[3.3.1] non-6-ene ( 2 3 ) gave 2-aza-adamantan-anti-4-01 (26) via a x-N+ type cyclization.Organic azides are well-known as excellent synthetic starting materials for various nitrogen-containing organic molecules, although, studies utilizing azide functionalization of carbocycles, particularly, bi-and tri-cycles seem, as yet, to be underdeveloped.2 We have therefore been pursuing attractive synthetic routes to aza-adamantane and related derivatives by utilizing azide functionalization of bi-and tri-carbocycles in order to study their biological proper tie^.^ Previously, we reported convenient and efficient synthesis of 4-azahomoadamant-4-ene and its 5-substituted derivatives by acidolysis and/or photolysis of 2-a~idoadamantanes.~ Here, we report the synthesis of 3-endo-azidomethyl-and -azidobicyclo[3.3.1]non-6-enes and their acidolysis behaviour, the latter providing novel routes to 4-azahomoadamant-4-enes and 4-hydroxy-2aza-adamant ane, respectively .* Eu(fod)3 = tris-(

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Section: -Endo-dideuterioazidometh~~~icyclo[331 Jnon-6-ene ['H2]-@mentioning

confidence: 99%

Synthesis and acidolysis of 3-endo-azidomethyl- and 3-endo-azidobicyclo[3.3.1]non-6-enes. A novel synthesis of 4-azahomoadamant-4-enes

Sasaki¹,

Eguchi²,

Toi³

et al. 1983

J. Chem. Soc., Perkin Trans. 1

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“…Similarly, the endo-d\ ketone (22) (>97% d) was prepared by quenching the enolate from 19 with hydrochloric acid. The deuterated trimethylsilyl enol ether (19) was conveniently prepared following base-catalyzed exchange of 15 in D20/NaOD.…”

Section: Synthesis and Stereochemistrymentioning

confidence: 99%

The octant rule. 7. Deuterium as an octant perturber

Lightner¹,

Gawroński²,

Bouman³

1980

J. Am. Chem. Soc.

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in solutions where úd+ is high enough to protonate most of the 8-MOP.Although we have made no real attempt to characterize the products of the slower reactions, both UV and NMR spectra show that substantial changes in the structure occur. We suspect that ring opening occurs to give either cisand/orZrans-6-hydroxy-5-benzofuranylacrylic acid, which would exist as carboxy-protonated conjugate acids or the related acylium ions in the strongly acidic media.The rates in sulfuric acid solutions were highest in 95% acid, the highest concentration at which the changes were monitored. However, the most rapid change of all was observed in 72% HCIO4. Although the rate variation in H2SO4 solutions could be correlated by a mechanism involving attack of a second proton on (8-MOP)H+, the same line of reasoning cannot account for the high rate in HCIO4.Acknowledgment. The part of this research conducted in Santa Cruz was supported by a grant from the Monsanto Chemical Co. We wish to thank Mr. George E. Babbitt for his help in acquisition of 13C NMR data and Dr. H. J. Yue for his assistance in the search for ESR signals.

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“…12,[16][17][18][19][20] Alternatively, it was proposed that the change of the vibrational ground state wave function due to the isotopic substitution, together with anharmonic effects, causes a slight variation of the average lengths of the bonds of the isotope, leading to a timeaveraged chiral structure. 10,11,[21][22][23][24][25][26][27][28][29] Furthermore, the experimental observations have been rationalized with a different polarizability/refractivity of the isotope 9,21,23,24 or a different electronegativity. 25 So far, quantum-mechanical calculations on semiempirical 21,25,26,28 and ab initio 27 levels of theory and also model calculations 9,22 have been reported in literature which at least qualitatively support the different explanations mentioned above.…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of the chiroptical properties of molecules with isotopically engendered chirality

Dierksen

Grimme

2006

The Journal of Chemical Physics

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There has been a considerable interest in the chiroptical properties of molecules whose chirality is exclusively due to an isotopic substitution and numerous examples for the electronic circular dichroism (CD) spectra of isotopically chiral systems have been reported in literature. Four different explanations have been proposed for the mechanism as to how the isotopic substitution induces a chiral perturbation of the otherwise achiral electronic wave function; however, up to now no conclusive answer has been given about the dominating effect responsible for the experimental observations. In this study we will present, for the first time, fully quantum-mechanical calculations of the CD spectra of three different molecular systems with isotopically engendered chirality. As examples, we consider the spectra of organic molecules with ketone and alpha-diketone carbonyl and diene chromophores. The effect of vibronic couplings for the reorientation of the electric and magnetic transition dipole moments is taken into account within the Herzberg-Teller approximation. The ground and excited state geometries and vibrational normal modes are obtained with (time-dependent) density functional theory [(TD)DFT], while the vibronic coupling effects are calculated at the TDDFT and density functional theory/multireference configuration interaction (DFT/MRCI) levels of theory. Generally, the band shapes of the experimental CD spectra are reproduced very well, and also the absolute CD intensities from the simulations are of the right order of magnitude. The sign and the intensity of the CD band are determined by a delicate balance of the contributions of a large number of individual vibronic transitions, and it is found that the vibrational normal modes with a large displacement are dominant. The separation of the calculated CD spectrum into the different contributions due to the overlap of the in-plane and out-of-plane components (regarding the symmetry plane of the unsubstituted molecule) of the electric and magnetic transition dipole moments yields information about the influence of the vibronic coupling effects for the reorientation of the corresponding transition dipole moments. In conclusion, the calculations clearly show that vibronic effects are responsible or at least dominant for the chiroptical properties of isotopically chiral organic molecules.

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Deuterium and the octant rule for ketones. Syntheses and circular dichroism data of chiral 4-deuterioadamantan-2-ones

Cited by 25 publications

References 10 publications

Synthesis and acidolysis of 3-endo-azidomethyl- and 3-endo-azidobicyclo[3.3.1]non-6-enes. A novel synthesis of 4-azahomoadamant-4-enes

Synthesis and acidolysis of 3-endo-azidomethyl- and 3-endo-azidobicyclo[3.3.1]non-6-enes. A novel synthesis of 4-azahomoadamant-4-enes

The octant rule. 7. Deuterium as an octant perturber

A theoretical study of the chiroptical properties of molecules with isotopically engendered chirality

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