1
|
Strzalko T, Wartski L, Corset J, Castellà-Ventura M, Froment F. Study of the Lithiated Phenylacetonitrile Monoanions and Dianions Formed According to the Lithiated Base Used (LHMDS, LDA, or n-BuLi). 2. Alkylation and Deuteriation Mechanism Study by Vibrational and NMR Spectroscopy and Quantum Chemistry Calculations. J Org Chem 2012; 77:6431-42. [DOI: 10.1021/jo300758g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Tekla Strzalko
- LSOM - CNRS/U-PSUD, Institut de Chimie Moléculaire et des Matériaux d’Orsay,
15 Rue Georges Clémenceau, 91405 Orsay Cedex, France
| | - Lya Wartski
- LSOM - CNRS/U-PSUD, Institut de Chimie Moléculaire et des Matériaux d’Orsay,
15 Rue Georges Clémenceau, 91405 Orsay Cedex, France
| | - Jacques Corset
- LADIR - CNRS/UPMC, 4 Place Jussieu, 75252 Paris Cedex 05, France
| | | | | |
Collapse
|
2
|
Scholz R, Hellmann G, Rohs S, Raabe G, Runsink J, Özdemir D, Luche O, Heß T, Giesen AW, Atodiresei J, Lindner HJ, Gais HJ. Experimental and Theoretical Investigation of the Enantiomerization of Lithium α-tert-Butylsulfonyl Carbanion Salts and the Determination of Their Structures in Solution and in the Crystal. European J Org Chem 2010. [DOI: 10.1002/ejoc.201000409] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
3
|
Munguia T, Bakir ZA, Cervantes-Lee F, Metta-Magana A, Pannell KH. The Utility of Sodium Diisopropylamide (NADA): Formation of a New Transition Metalate via Silyl Migration Chemistry, [(η5-Me3SiC5H4)Fe(CO)(PPh3)]−Na+ (SiFpPNa), and Resulting Thermal Rearrangements of the Complexes SiFpP−CH2SiMe2R (R = H, SiMe3) to SiFpP−SiMe2CH2R. Organometallics 2009. [DOI: 10.1021/om9006032] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Teresita Munguia
- Department of Chemistry, University of Texas at El Paso, El Paso, Texas 79968
| | - Zaynab A. Bakir
- Department of Chemistry, University of Texas at El Paso, El Paso, Texas 79968
| | | | | | - Keith H. Pannell
- Department of Chemistry, University of Texas at El Paso, El Paso, Texas 79968
| |
Collapse
|
4
|
Abstract
The author reviews how his early love for theoretical organic chemistry led to experimental research and the extended search for quantitative correlations between experiment and quantum calculations. The experimental work led to ion pair acidities of alkali-organic compounds and most recently to equilibria and reactions of lithium and cesium enolates in THF. This chemistry is now being modeled by ab initio calculations. An important consideration is the treatment of solvation in which coordination of the alkali cation with the ether solvent plays a major role.
Collapse
Affiliation(s)
- Andrew Streitwieser
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
| |
Collapse
|
5
|
Corset J, Castellà-Ventura M, Froment F, Strzalko T, Wartski L. Identification of the monoanions and of their complexes with lithium salts possibly formed in solution during the alkylation of lithiated phenylacetonitrile dianions: infrared spectroscopy and density functional theory calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 68:1340-6. [PMID: 17466572 DOI: 10.1016/j.saa.2007.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 02/19/2007] [Indexed: 05/15/2023]
Abstract
The carbanionic species possibly formed during the first alkylation step of phenylacetonitrile lithiated anion by CH(3)I and PhCH(2)Cl in THF-hexane solution and their complexes with the lithium salt formed have been observed by infrared spectrometry and characterized by density functional theory calculations. The spectra of alkylated phenylacetonitrile lithiated anion monomers and dimers have been identified in good agreement with calculations. The wave numbers of the vibrational modes of the alkylated species differ significantly from those of PhCHCNLi species, but do not depend appreciably on the substituent nature. Nevertheless with the methyl substituent, the isomerization equilibrium of the monomer is noticeably shifted toward the bridged (C-lithiated) species. The formation of a heterodimer at the expense of the dimer after addition of LiCl has been confirmed by experiment.
Collapse
Affiliation(s)
- Jacques Corset
- LADIR, CNRS et UPMC (UMR 7075), 2 Rue Henri Dunant, BP 28, 94320, Thiais, France
| | | | | | | | | |
Collapse
|
6
|
Binev YI, Georgieva MK, Novkova SI. The conversion of phenylpropanedinitrile (phenylmalononitrile) into the carbanion, followed by IR spectra, ab initio and DFT force field calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:3041-3052. [PMID: 14583279 DOI: 10.1016/s1386-1425(03)00118-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The spectral and structural changes, caused by the conversion of phenylpropanedinitrile (phenylmalononitrile) into the carbanion, have been followed by IR spectra, ab initio HF, MP2 and DFT BLYP force field calculations. In agreement between theory and experiment, the conversion is accompanied with strong frequency decreases (with 114 cm(-1), mean value) of the cyano stretching bands nu(C triple bond N), dramatic increases in the corresponding integrated intensities (136-fold, total value), strong enhancement of the nu(C triple bond N) vibrational coupling and other essential spectral changes. According to the calculations, the strongest structural changes take place at the carbanionic center: (i) shortenings of the Cz-Ph and Cz-CN bonds with 0.064-0.092 A, and increases in the corresponding bond orders with 0.14-0.21 U; (ii) simultaneous enlargements of the bond angles at the same carbon atom with 7.6 degrees -9.7 degrees, as from tetrahedral its configuration becomes trigonal. The carbanionic charge is distributed between the two cyano groups (0.44-0.52 e(-)), phenyl ring (0.31-0.34 e(-)) and carbanionic center (0.14-0.25 e(-)). The formation of moderately strong (CH(3))(2)S=O...H-C(CN)(2)C(6)H(5) hydrogen bonds has been found experimentally.
Collapse
Affiliation(s)
- Yuri I Binev
- Institute of Organic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
| | | | | |
Collapse
|
7
|
Corset J, Castellà-Ventura M, Froment F, Strzalko T, Wartski L. Study of the lithiated phenylacetonitrile monoanions and dianions formed according to the lithiated base used (LHMDS, LDA, or n-BuLi). 1. Evidence of heterodimer ("Quadac") or dianion formation by vibrational spectroscopy. J Org Chem 2003; 68:3902-11. [PMID: 12737570 DOI: 10.1021/jo020492t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is evidenced through vibrational spectroscopy that a heterodimer or "Quadac" is formed when an excess of base (LHMDS, LDA, or n-BuLi) is added to PhCH(2)CN in THF, THF-hexane, or THF-toluene solution. The amount of heterodimer increases with the pK(H)(a) of the lithiated base. A dianionic species may be formed through decomposition of this heterodimer if the pK(H)(a) of the base is sufficiently high, as in the case of n-BuLi. With LDA, only a very small amount of dianion is observed, and with LHMDS, no dianion is detected. The predominant dianionic species observed are the linear and bridged separated ion pairs of the dilithiated dianion. The presence of the amine in the medium is of paramount importance. The PhCHCNLi monomer-dimer equilibrium is entropy driven toward the dimer solvated by the amine.
Collapse
Affiliation(s)
- Jacques Corset
- LADIR - CNRS (UMR 7075), 2 Rue Henri Dunant, BP 28, 94320 Thiais, France
| | | | | | | | | |
Collapse
|
8
|
Carlier PR. Configurational stability of chiral lithiated cyclopropylnitriles: a density functional study. Chirality 2003; 15:340-7. [PMID: 12666242 DOI: 10.1002/chir.10222] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chiral, configurationally stable lithiated nitriles would be valuable intermediates for asymmetric carbon-carbon bond-forming reactions. To gain insight into the design of such species, Walborsky's attempted enantioselective deprotonation/trapping reactions of a chiral cyclopropylnitrile were studied computationally up to the MP2(fc)/6-31+G* and B3LYP/6-31+G* levels. Investigation of cyclopropylnitrile/LiNH(2) deprotonation transition structures demonstrated a significant (20-23 kcal/mol) kinetic preference for N-lithiation, and a facile (4-6 kcal/mol barrier) "conducted tour" racemization pathway for the N-lithiated nitrile product. Addition of a model directing group (formyl) to the beta-carbon of the cyclopropyl ring is predicted to significantly favor C-lithiation over N-lithiation, both kinetically and thermodynamically. Thus, chiral beta-Lewis base substituted cyclopropylnitriles may serve as precursors to chiral, configurationally stable organolithium reagents.
Collapse
Affiliation(s)
- Paul R Carlier
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, USA.
| |
Collapse
|
9
|
Corset J, Castellà-Ventura M, Froment F, Strzalko T, Wartski L. Structural and vibrational characterization of the mono and dilithiated species derived from phenylacetonitrile in THF by infrared and Raman spectroscopy and density functional theory calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2002; 58:1971-1986. [PMID: 12164496 DOI: 10.1016/s1386-1425(01)00648-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The structures and spectra of mono and dianionic species derived from PhCH2CN under the action of an organic base LHMDS or n-BuLi in THF solution have been investigated by vibrational spectroscopy and DFT calculations. The assignments previously proposed for the monoanion, the bridged, linear and dimeric monoanionic ion pairs compare well with the calculated ones. The addition of HMPA to a THF solution of PhCHCNLi leads to the formation of an HMPA solvated linear ion pair, distinguishable from the bridged ion pair by the wave number of the 8a v(CC) phenyl ring mode. The calculated structure of the phenylacetonitrile anion in the (PhCHCNLi, CH3Li) mixed dimer or 'Quadac' is very similar to that in the linear ion pair or in the dimer and to that observed by X-ray in (PhCHCNLi, [CH(CH9)2]2NLi) 'Quadac'. The structure of the anion is planar, indicating a charge delocalization from the benzene ring to the -CHCN group. The calculated spectra of the free, mono and dilithiated dianionic species compare well with the experimental ones of the species formed under addition of more than one equivalent of n-BuLi. The structure of the >C-C-CN2- group is very close to that of an imine. The v(CN) bands of the free, mono and dilithiated dianionic species are located at 1912, 1930 and 1890 cm(-1), respectively. The large wave number shift observed between the free monoanion and dianion (approximately 176 cm(-1)), in good accordance with the calculated one (170 cm(-1)) allows differentiating mono and dianionic species. The shifts observed for the 8a and 19a v(CC) phenyl ring modes, although much smaller, also allows discriminating the different species. These small shifts indicate a small variation of the electronic delocalization in the benzene ring in agreement with the calculations.
Collapse
|
10
|
Fleming FF, Wang Q, Steward OW. gamma-hydroxy unsaturated nitriles: chelation-controlled conjugate additions. Org Lett 2000; 2:1477-9. [PMID: 10814477 DOI: 10.1021/ol005816j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction--see text] Chelation between gamma-hydroxy unsaturated nitriles and Grignard reagents promotes an otherwise difficult anionic conjugate addition reaction. The intermediate chelate is readily generated by deprotonation with t-BuMgCl followed by the addition of a second Grignard reagent that triggers an intramolecular conjugate addition. Structurally diverse Grignard reagents add with equal efficiency, providing an intermediate anion that stereoselectively alkylates BnBr in an overall addition-alkylation reaction.
Collapse
Affiliation(s)
- F F Fleming
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282-1530, USA.
| | | | | |
Collapse
|
11
|
Fleming FF, Shook BC, Jiang T, Steward OW. beta-Siloxy unsaturated nitriles: stereoselective cyclizations to cis- and trans-decalins. Org Lett 1999; 1:1547-50. [PMID: 10836022 DOI: 10.1021/ol990854s] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[formula: see text] beta-Siloxy unsaturated nitriles are excellent precursors to enolate and nitrile anions that cyclize to cis- and trans-decalins, respectively. The stereoelectronic requirements of endocyclic enolates and exocyclic nitrile anions are complementary, providing cis- and trans-decalins from a common intermediate. This cyclization allows the synthesis of diastereomeric cis- and trans-decalins containing a contiguous array of quaternary-tertiary-quaternary stereocenters.
Collapse
Affiliation(s)
- F F Fleming
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA.
| | | | | | | |
Collapse
|