51
|
Zhang Y, Yu C, Ji Y, Wang W. Diastereo- and Enantioselective Organocatalytic Direct Conjugate Addition of γ-Butenolide to Chalcones. Chem Asian J 2008; 5:1303-6. [DOI: 10.1002/asia.201000014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
52
|
de Bettencourt-Dias A, Viswanathan S, Rollett A. Thiophene-Derivatized Pybox and Its Highly Luminescent Lanthanide Ion Complexes. J Am Chem Soc 2007; 129:15436-7. [DOI: 10.1021/ja076485+] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
53
|
Palombi L, Acocella MR, Villano R, Scettri A. Eu(OTf)3-catalyzed oxidation of 5-alkylidene-4,5-dihydrofurans: A new approach to functionalized furylhydroperoxides. CATAL COMMUN 2007. [DOI: 10.1016/j.catcom.2007.01.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
54
|
Belostotskii AM, Albeck A, Hassner A. Asymmetric Induction by a Remote Chiral Substituent – Computationally Determined Stereodifferentiation in Michael Additions of α-Lithiated Allyl Sulfones. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700245] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
55
|
Evans DA, Fandrick KR, Song HJ, Scheidt KA, Xu R. Enantioselective Friedel-Crafts alkylations catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes. J Am Chem Soc 2007; 129:10029-41. [PMID: 17658808 DOI: 10.1021/ja072976i] [Citation(s) in RCA: 240] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enantioselective Friedel-Crafts addition of a variety of indoles catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes (Sc(III)-pybox) was accomplished utilizing a series of beta-substituted alpha,beta-unsaturated phosphonates and alpha,beta-unsaturated 2-acyl imidazoles. The acyl phosphonate products were efficiently transformed into esters and amides, whereas the acyl imidazole adducts were converted to a broader spectrum of functionalities such as esters, amides, carboxylic acids, ketones, and aldehydes. The sense of stereoinduction and level of enantioselectivity were found to be functions of the size of the substrate employed, the substitution on the ligand, and the catalyst loading. Molecular modeling of the catalyst with the bound substrates was performed based on the crystal structures of the catalyst complexes and the sense of stereoinduction observed in the addition reaction. Nonlinear effects over a range of catalyst concentrations implicate a mononuclear complex as the active catalyst.
Collapse
Affiliation(s)
- David A Evans
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
| | | | | | | | | |
Collapse
|
56
|
Abe AMM, Sauerland SJK, Koskinen AMP. Highly Enantioselective Conjugate Addition of Thiols Using Mild Scandium Triflate Catalysis. J Org Chem 2007; 72:5411-3. [PMID: 17550292 DOI: 10.1021/jo070492z] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Sc complex of (4S,5S)-diphenyl PYBOX 1 was found to serve as a catalyst for the asymmetric conjugate addition reactions between various thiols and 3-crotonoyl-2-oxazolidinone, affording the corresponding adducts in good yields and high enantioselectivies (up to 92% ee). A new improved method for making (4S,5S)-diphenyl PYBOX is presented.
Collapse
Affiliation(s)
- Aki M M Abe
- Laboratory of Organic Chemistry, Helsinki University of Technology, P.O.B. 6100, FI-02015 TKK, Finland
| | | | | |
Collapse
|
57
|
Desimoni G, Faita G, Mella M, Piccinini F, Toscanini M. Pybox/Lanthanide-Catalysed Diels–Alder Reactions with an Unsaturated α-Oxo Ester or 3-Alkenoyl-2-oxazolidinone as Dienophile: The Sense of Stereoinduction in Five- or Six-Membered Bidentate Reagent Coordination. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600955] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
58
|
Suga H, Takemoto H, Kakehi A. Lewis Acid-Catalyzed Michael Addition Reactions of N-Boc-2-silyloxypyrroles to 3-Acryloyl-2-oxazolidinone. HETEROCYCLES 2007. [DOI: 10.3987/com-06-10966] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
59
|
Desimoni G, Faita G, Piccinini F, Toscanini M. Enantioselective Mukaiyama-Aldol Reaction of Pyruvates and 1-Phenyl- 1-trimethylsilyloxyethene Catalyzed by Lanthanide/Pybox Complexes. European J Org Chem 2006. [DOI: 10.1002/ejoc.200600716] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
60
|
Suga H, Suzuki T, Inoue K, Kakehi A. Asymmetric cycloaddition reactions between 2-benzopyrylium-4-olates and 3-(2-alkenoyl)-2-oxazolidinones in the presence of 2,6-bis(oxazolinyl)pyridine-lanthanoid complexes. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.07.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
61
|
Desimoni G, Faita G, Jørgensen KA. C2-Symmetric Chiral Bis(Oxazoline) Ligands in Asymmetric Catalysis. Chem Rev 2006; 106:3561-651. [PMID: 16967916 DOI: 10.1021/cr0505324] [Citation(s) in RCA: 652] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Giovanni Desimoni
- Department of Organic Chemistry, University of Pavia, Viale Taramelli 10, 27100 Pavia, Italy.
| | | | | |
Collapse
|
62
|
Tse MK, Bhor S, Klawonn M, Anilkumar G, Jiao H, Döbler C, Spannenberg A, Mägerlein W, Hugl H, Beller M. Ruthenium-Catalyzed Asymmetric Epoxidation of Olefins Using H2O2, Part I: Synthesis of New ChiralN,N,N-Tridentate Pybox and Pyboxazine Ligands and Their Ruthenium Complexes. Chemistry 2006; 12:1855-74. [PMID: 16440390 DOI: 10.1002/chem.200501261] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The synthesis of chiral tridentate N,N,N-pyridine-2,6-bisoxazolines 3 (pybox ligands) and N,N,N-pyridine-2,6-bisoxazines 4 (pyboxazine ligands) is described in detail. These novel ligands constitute a useful toolbox for the application in asymmetric catalysis. Compounds 3 and 4 are conveniently prepared by cyclization of enantiomerically pure alpha- or beta-amino alcohols with dimethyl pyridine-2,6-dicarboximidate. The corresponding ruthenium complexes are efficient asymmetric epoxidation catalysts and have been prepared in good yield and fully characterized by spectroscopic means. Four of these ruthenium complexes have been characterized by X-ray crystallography. For the first time the molecular structure of a pyboxazine complex [2,6-bis-[(4S)-4-phenyl-5,6-dihydro-4H-[1,3]oxazinyl]pyridine](pyridine-2,6-dicarboxylate)ruthenium (S)-2 aa, is presented.
Collapse
Affiliation(s)
- Man Kin Tse
- Leibniz-Institut für Organische Katalyse an der Universität Rostock e.V. Albert-Einstein-Strasse 29a, 18059 Rostock (Germany)
| | | | | | | | | | | | | | | | | | | |
Collapse
|
63
|
Aspinall HC, Bickley JF, Greeves N, Kelly RV, Smith PM. Lanthanide Pybox Complexes as Catalysts for Enantioselective Silylcyanation of Aldehydes. Organometallics 2005. [DOI: 10.1021/om050197+] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
64
|
Desimoni G, Faita G, Guala M, Laurenti A, Mella M. A New Pyridine-2,6-bis(oxazoline) for Efficient and Flexible Lanthanide-Based Catalysts of Enantioselective Reactions with 3-Alkenoyl-2-oxazolidinones. Chemistry 2005; 11:3816-24. [PMID: 15827979 DOI: 10.1002/chem.200401213] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A new pyridine-2,6-bis(oxazoline) (4) has been easily synthesised from the reaction of (1S,2S)-2-amino-1-phenylpropane-1,3-diol (1) and dimethyl pyridine-2,6-dicarboximidate (2), followed by TIPS (TIPS=triisopropylsilyl) protection of the 4'-CH2OH group. The catalysts derived from 4 and eight lanthanide(III) triflates have been tested over three reactions involving 3-acryloyl- and 3-crotonoyloxazolidinones (5 a,b): the Diels-Alder (DA) reaction with cyclopentadiene, the 1,3-dipolar cycloaddition with diphenyl nitrone and the Mukaiyama-Michael reaction with 2-trimethylsilyloxyfuran. Several reactions exhibit very good enantioselectivity (ee>90 %), and the opposite enantiomers can be easily obtained simply by changing the cation. This specific feature of the ligand can be appreciated in the DA reaction of 5 a, since the catalyst [Sc(III)4] gives the adduct (2'S)-9 a with 99 % ee, whereas the catalyst [Y(III)4] gives the opposite enantiomer with 95 % ee. A rationale of the enantioselectivity is proposed on the basis of the NMR spectra of La-based complexes involving 4 and 5 as ligands.
Collapse
Affiliation(s)
- Giovanni Desimoni
- Dipartimento di Chimica Organica, Università di Pavia, Viale Taramelli 10, 27100 Pavia, Italy.
| | | | | | | | | |
Collapse
|
65
|
Harada T, Adachi S, Wang X. Dimethylsilyl Ketene Acetal as a Nucleophile in Asymmetric Michael Reaction: Enhanced Enantioselectivity in Oxazaborolidinone-Catalyzed Reaction. Org Lett 2004; 6:4877-9. [PMID: 15606089 DOI: 10.1021/ol048071g] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Dimethylsilanyl [Me2Si(H)] ketene S,O-acetal 6b is an effective nucleophile that retards the undesirable Si+-catalyzed racemic pathway in the oxazaborolidinone-catalyzed asymmetric Michael reaction. Through the further suppression of the Si+-catalyzed pathway by carrying out the reaction in the presence of 2,6-diisopropylphenol and t-BuOMe as additives, enantioselectivity up to 98% ee could be achieved for a variety of acyclic enones.
Collapse
Affiliation(s)
- Toshiro Harada
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
| | | | | |
Collapse
|
66
|
Bayardon J, Sinou D, Guala M, Desimoni G. Applications of enantiopure 4,5-diphenyl substituted box and pybox ligands in asymmetric catalysis. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.tetasy.2004.08.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
67
|
McManus HA, Guiry PJ. Recent Developments in the Application of Oxazoline-Containing Ligands in Asymmetric Catalysis. Chem Rev 2004; 104:4151-202. [PMID: 15352789 DOI: 10.1021/cr040642v] [Citation(s) in RCA: 567] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Helen A McManus
- Centre for Synthesis and Chemical Biology, Conway Institute of Biomolecular and Biomedical Research, Department of Chemistry, University College Dublin, Belfield, 4, Ireland
| | | |
Collapse
|
68
|
Synthesis of new central and planar chiral enantiomerically pure 5-ferrocenyl-oxazolines and a 5-ferrocenyl-thiazoline. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.tetasy.2004.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
69
|
Suga H, Kitamura T, Kakehi A, Baba T. Asymmetric Michael addition reactions of 2-silyloxyfurans catalyzed by binaphthyldiimine–Ni(ii) complexes. Chem Commun (Camb) 2004:1414-5. [PMID: 15179491 DOI: 10.1039/b402826k] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N,N'-Bis(2-quinolylmethylene)-1,1'-binaphthyl-2,2'-diamine-Ni(II) complex and analogous complexes were found to be efficient chiral Lewis acid catalysts for the asymmetric Michael addition reactions between 2-silyloxyfurans and 3-alkenoyl-2-oxazolidinones, for which asymmetric inductions of up to 97% ee were obtained.
Collapse
Affiliation(s)
- Hiroyuki Suga
- Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University, Wakasato, Nagano 380-8553, Japan.
| | | | | | | |
Collapse
|
70
|
Furuno H, Hayano T, Kambara T, Sugimoto Y, Hanamoto T, Tanaka Y, Jin YZ, Kagawa T, Inanaga J. Chiral rare earth organophosphates as homogeneous Lewis acid catalysts for the highly enantioselective hetero-Diels–Alder reactions. Tetrahedron 2003. [DOI: 10.1016/j.tet.2003.06.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
71
|
Wang X, Adachi S, Iwai H, Takatsuki H, Fujita K, Kubo M, Oku A, Harada T. Enantioselective Lewis Acid-Catalyzed Mukaiyama−Michael Reactions of Acyclic Enones. Catalysis by allo-Threonine-Derived Oxazaborolidinones. J Org Chem 2003; 68:10046-57. [PMID: 14682699 DOI: 10.1021/jo035379x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
allo-Threonine-derived O-aroyl-B-phenyl-N-tosyl-1,3,2-oxazaborolidin-5-ones 1g,n catalyze the asymmetric Mukaiyama-Michael reaction of acyclic enones with a trimethylsilyl ketene S,O-acetal in high enantioselectivity. A range of alkenyl methyl ketones is successfully employed as Michael acceptors affording ee values of 85-90% by using 10 mol % of the catalyst. The use of 2,6-diisopropylphenol and tert-butyl methyl ether as additives is found to be essential to achieve high enantioselectivity in these reactions. The effects of the additives are discussed in terms of the retardation of an Si(+)-catalyzed racemic pathway, which seriously deteriorates the enantioselectivity of asymmetric Mukaiyama-Michael reactions. A working model for asymmetric induction is proposed based on correlation between catalyst structures and enantioselectivities.
Collapse
Affiliation(s)
- Xiaowei Wang
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | | | | | | | | | |
Collapse
|
72
|
Desimoni G, Faita G, Guala M, Pratelli C. Different Lanthanide Ions and the Pybox Substituents Induce the Reverse of the Sense of Induction in the Enantioselective Diels−Alder Reaction between Acryloyloxazolidinone and Cyclopentadiene. J Org Chem 2003; 68:7862-6. [PMID: 14510567 DOI: 10.1021/jo034215d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Diels-Alder reaction of cyclopentadiene with acryloyl-1,3-oxazolidin-2-one is catalyzed by (R,R)-i-Pr- and (R,R)-Ph-pybox (5 and 6)/lanthanide(III) triflate complexes. The enantioselectivity of the reaction is influenced by 4 A molecular sieves; moreover, the absolute sense of the enantioselection was found to be a function of the nature of the substituents on the chiral ligand (e.g., aromatic vs alkyl groups) as well as of the specific cation employed. In particular, seven lanthanide triflates were tested and a regular variation of the enantioselectivity as a function of the cation ionic radius was evidenced. The different sense of induction can be rationalized by assuming two competitive reacting complexes with different coordination number, which favor the attack on the opposite heterotopic faces of the coordinated dienophile.
Collapse
Affiliation(s)
- Giovanni Desimoni
- Dipartimento di Chimica Organica, Università di Pavia, viale Taramelli 10, 27100 Pavia, Italy.
| | | | | | | |
Collapse
|
73
|
Desimoni G, Faita G, Quadrelli P. Pyridine-2,6-bis(oxazolines), helpful ligands for asymmetric catalysts. Chem Rev 2003; 103:3119-54. [PMID: 12914494 DOI: 10.1021/cr020004h] [Citation(s) in RCA: 385] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giovanni Desimoni
- Dipartimento di Chimica Organica, Università di Pavia, Viale Taramelli 10, I-27100 Pavia, Italy
| | | | | |
Collapse
|
74
|
Hayano T, Sakaguchi T, Furuno H, Ohba M, Okawa H, Inanaga J. Novel Cerium(III)–(R)-BNP Complex as a Storable Chiral Lewis Acid Catalyst for the Enantioselective Hetero-Diels–Alder Reaction. CHEM LETT 2003. [DOI: 10.1246/cl.2003.608] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
75
|
van Lingen HL, Zhuang W, Hansen T, Rutjes FPJT, Jørgensen KA. Formation of optically active chromanes by catalytic asymmetric tandem oxa-Michael addition-Friedel-Crafts alkylation reactions. Org Biomol Chem 2003; 1:1953-8. [PMID: 12945779 DOI: 10.1039/b303353h] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel tandem reaction involving an oxa-Michael addition, followed by a Friedel-Crafts alkylation has been developed. This catalytic tandem reaction, which provides facile and efficient access to optically active functionalised chromanes, proceeds under the influence of bisoxazoline-based catalysts to give diastereomerically pure products in enantioselectivities up to 81% and excellent yields. The optimisation studies, the scope of the reaction, and a model that on the basis of PM3 calculations predicts the outcome of the reaction will be detailed.
Collapse
Affiliation(s)
- Hester L van Lingen
- Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | | | | | | | | |
Collapse
|
76
|
|
77
|
Aspinall HC. Chiral lanthanide complexes: coordination chemistry and applications. Chem Rev 2002; 102:1807-50. [PMID: 12059255 DOI: 10.1021/cr010288q] [Citation(s) in RCA: 441] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Helen C Aspinall
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, U.K.
| |
Collapse
|
78
|
Desimoni G, Faita G, Guala M, Pratelli C. An efficient catalyst for highly enantioselective exo-Diels–Alder reaction between alkenoyl-1,3-oxazolidin-2-ones and cyclopentadiene. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00201-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
79
|
Chapter 5.3 Five-membered ring systems: Furans and benzofurans. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0959-6380(02)80009-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|