Asymmetric allylation of α-ketoester-derived N-benzoylhydrazones promoted by chiral sulfoxides/N-oxides lewis bases: Highly enantioselective synthesis of quaternary α-substituted α-allyl-α-amino acids

Chirality

Volumn 25, Issue 9, 2013, Pages 529-540

  Reyes Rangel, Gloria ^a   Bandala, Yamir ^a,b   García Flores, Fred ^a   Juaristi, Eusebio ^a  

^a DEPARTAMENTO DE FÍSICA   (Mexico)

^b INSTITUTO DE BIOTECNOLOGÍA   (Mexico)

Author keywords

allyl amino acids; Asymmetric allylation; chiral sulfoxides; Lewis bases; quaternary carbons

Indexed keywords

ALLYL COMPOUND; AMINO ACID; ESTER DERIVATIVE; HYDRAZINE DERIVATIVE; HYDRAZONE DERIVATIVE; LEWIS BASE; SULFOXIDE;

ALLYLATION; ARTICLE; CATALYST; CHEMICAL STRUCTURE; CHIRALITY; CIRCULAR DICHROISM; ELECTRONIC CIRCULAR DICHROISM; ENANTIOMER; ENANTIOSELECTIVITY; PRIORITY JOURNAL; SUBSTITUTION REACTION; SYNTHESIS;

ASYMMETRIC ALLYLATION; CHIRAL SULFOXIDES; LEWIS BASES; QUATERNARY CARBONS; Α-ALLYL-Α-AMINO ACIDS;

ALDEHYDES; ALLYL COMPOUNDS; AMINO ACIDS; CATALYSIS; CIRCULAR DICHROISM; ESTERS; HYDRAZONES; KETONES; LEWIS BASES; MOLECULAR STRUCTURE; STEREOISOMERISM; SULFOXIDES;

EID: 84883024381     PISSN: 08990042     EISSN: 1520636X     Source Type: Journal    
DOI: 10.1002/chir.22159     Document Type: Article

References (124)

1. Kočovský P, Malkov V,. Enantioselective organocatalysis, Vol. 7. Weinheim, Germany: Wiley-VCH; 2007. p. 255-264.
2. Kobayashi S, Mori Y, Fossey JS, Salter MM,. Catalytic enantioselective formation of C-C bonds by addition to imines and hydrazones: a ten-year update. Chem Rev 2011; 111: 2626-2704.
3. Yus M, González-Gõmez JC, Foubelo F,. Catalytic enantioselective allylation of carbonyl compounds and imines. Chem Rev 2011; 111: 7774-7854.
4. Lin GQ, Xu MH, Zhong YM, Sun XW,. An advance on exploring N-tert-butanesulfinyl imines in asymmetric synthesis of chiral amines. Acc Chem Res 2008; 41: 831-840.
5. Galliford CV, Scheidt KA,. Pyrrolidinyl-spirooxindole natural products as inspirations for the development of potential therapeutic agents. Angew Chem Int Ed 2007; 46: 8748-8758.
6. Denhez C, Vasse JL, Harakat D, Szymoniak J,. Asymmetric synthesis of di- and trisubstituted pyrrolidinones via zirconium-mediated intramolecular coupling of N-3-alkenyl carbamates. Tetrahedron: Asymmetry 2007; 18: 424-434.
7. Kropf JE, Meigh IC, Bebbington MWP, Weinreb SM,. Studies on a total synthesis of the microbial immunosuppressive agent FR901483. J Org Chem 2006; 71: 2046-2055.
8. Ding H, Friestad GK,. Asymmetric addition of allylic nucleophiles to imino compounds. Synthesis 2005; 2815-2829.
9. Schmidt AM, Eilbracht P,. Synthesis of pharmacologically relevant indoles with amine side chains via tandem hydroformylation/Fischer indole synthesis. J Org Chem 2005; 70: 5528-5535.
10. Marti C, Carreira EM,. Construction of spiro[pyrrolidine-3,3'-oxindoles]- recent applications to the synthesis of oxindole alkaloids. Eur J Org Chem 2003: 2209-2219.
11. Agami C, Couty F, Evano G,. Enantioselective synthesis of 2-substituted-N-Boc-â-μ-4,5-piperidines. Tetrahedron: Asymmetry 2000; 11: 4639-4643.
12. Kobayashi S, Ishitani H,. Catalytic enantioselective addition to imines. Chem Rev 1999; 99: 1069-1094.
13. Puentes CO, Kouznetsov V,. Recent advancements in the homoallylamine chemistry. J Heterocycl Chem 2002; 39: 595-614.
14. Steinig AG, Spero DM,. Amines via nucleophilic 1,2-addition to ketimines. Construction of nitrogen-substituted quaternary carbon atoms, a review. Org Prep Proced Int 2000; 32: 205-234.
15. Bloch R,. Additions of organometallic reagents to C = N bonds: reactivity and selectivity. Chem Rev 1998; 98: 1407-1438.
16. Enders D, Reinhold U,. Asymmetric synthesis of amines by nucleophilic 1,2-addition of organometallic reagents to the CN-double bond. Tetrahedron: Asymmetry 1997; 8: 1895-1946.
17. Pellissier H,. Asymmetric organocatalytic cycloadditions. Tetrahedron 2012; 68: 2197-2232.
18. Pellissier H,. Recent developments in asymmetric organocatalytic domino reactions. Adv Synth Catal 2012; 354: 237-294.
19. Palomo C, Oiarbide M, Lõpez R,. Asymmetric organocatalysis by chiral Brønsted bases: implications and applications. Chem Soc Rev 2009; 38: 632-653.
20. MacMillan DWC,. The advent and development of organocatalysis. Nature 2008; 455: 304-308.
21. Yu X, Wang W,. Hydrogen-bond-mediated asymmetric catalysis. Chem Asian J 2008; 3: 516-532.
22. Dondoni A, Massi A,. Asymmetric organocatalysis: from infancy to adolescence. Angew Chem Int Ed 2008; 47: 4638-4660.
23. Melchiorre P, Marigo M, Carlone A, Bartoli G,. Asymmetric aminocatalysis-gold rush in organic chemistry. Angew Chem Int Ed 2008; 47: 6138-6171.
24. Mukherjee S, Yang JW, Hoffmann S, List B,. Asymmetric enamine catalysis. Chem Rev 2007; 107: 5471-5569.
25. Enders D, Niemeier O, Henseler A,. Organocatalysis by N-heterocyclic carbenes. Chem Rev 2007; 107: 5606-5655.
26. Colby Davie EA, Mennen SM, Xu Y, Miller SJ,. Asymmetric catalysis mediated by synthetic peptides. Chem Rev 2007; 107: 5759-5812.
27. Hernández JG, Juaristi E,. Recent efforts directed to the development of more sustainable asymmetric organocatalysis. Chem Commun 2012; 48: 5396-5409.
28. Doyle AG, Jacobsen EN,. Small-molecule H-bond donors in asymmetric catalysis. Chem Rev 2007; 107: 5713-5743.
29. Dalko PI, editor. Enantioselective organocatalysis reactions and experimental procedures. Weinheim, Germany: Wiley-VCH; 2007.
30. Berkessel A, Gröger H,. in Asymmetric organocatalysis: from biomimetic concepts to applications in asymmetric synthesis. Weinheim, Germany: Wiley-VCH; 2005.
31. Keck GE, Enholm EJ,. Homoallylamines from aldimines and allylstannanes. J Org Chem 1985; 50: 146-147.
32. Hoffmann RW, Endesfelder A,. Diastereoselective addition of crotylboronates to oximes. Liebigs Ann Chem 1987; 215-219.
33. Yamamoto Y, Asao N,. Selective reactions using allylic metals. Chem Rev 1993; 93: 2207-2293.
34. Sugiura M, Kobayashi S,. N-Acylhydrazones as versatile electrophiles for the synthesis of nitrogen-containing compounds. Angew Chem Int Ed 2005; 44: 5176-5186.
35. Kobayashi S, Sugiura M, Ogawa C,. Neutral coordinate-organocatalysts in organic synthesis: allylation of acylhydrazones with allyltrichlorosilanes. Adv Synth Catal 2004; 346: 1023-1034.
36. Ogawa C, Sugiura M, Kobayashi S,. Stereospecific, enantioselective allylation of α-hydrazono esters by using allyltrichlorosilanes with BINAP dioxides as neutral-coordinate organocatalysts. Angew Chem Int Ed 2004; 43: 6491-6493.
37. Denmark SE, Fu J,. Catalytic enantioselective addition of allylic organometallic reagents to aldehydes and ketones. Chem Rev 2003; 103: 2763-2794.
38. Kobayashi S, Ogawa C, Konishi H, Sugiura M,. Chiral sulfoxides as neutral coordinate-organocatalysts in asymmetric allylation of N-acylhydrazones using allyltrichlorosilanes. J Am Chem Soc 2003; 125: 6610-6611.
39. Hirabayashi R, Ogawa C, Sugiura M, Kobayashi S,. Highly stereoselective synthesis of homoallylic amines based on addition of allyltrichlorosilanes to benzoylhydrazones. J Am Chem Soc 2001; 123: 9493-9499.
40. Yamamoto H, editor. Lewis acids in organic synthesis, Vols. 1 and 2. Weinheim, Germany: Wiley-VCH; 1999.
41. Chuit C, Corriu RJP, Reye C, Young JC,. Reactivity of penta- and hexacoordinate silicon compounds and their role as reaction intermediates. Chem Rev 1993; 93: 1371-1448.
42. Ogawa C, Sugiura M, Kobayashi S,. Stereoselective synthesis of both syn- and anti-N-tert-alkylamines using highly stereospecific crotylation of ketone-derived acylhydrazones with crotyltrichlorosilanes. J Org Chem 2002; 67: 5359-5364.
43. Kobayashi S, Nishio K,. Facile and highly stereoselective synthesis of homoallylic alcohols using organosilicon intermediates. J Org Chem 1994; 59: 6620-6628.
44. Malkov AV, Kočovský P,. Chiral N-oxides in asymmetric catalysis. Eur J Org Chem 2007; 29-36.
45. Malkov AV, Dufková L, Farrugia L, Kočovský P,. Quinox, a quinoline-type N-oxide, as organocatalyst in the asymmetric allylation of aromatic aldehydes with allyltrichlorosilanes: the role of arene-arene interactions. Angew Chem Int Ed 2003; 42: 3674-3677.
46. Nakajima M, Saito M, Hashimoto S,. Selective synthesis of optically active allenic and homopropargylic alcohols from propargyl chloride. Tetrahedron: Asymmetry 2002; 13: 2449-2452.
47. Shimada T, Kina A, Ikeda S, Hayashi T,. A novel axially chiral 2,2'-bipyridine N,N'-dioxide. Its preparation and use for asymmetric allylation of aldehydes with allyl(trichloro)silane as a highly efficient catalyst. Org Lett 2002; 4: 2799-2801.
48. Nakajima M, Saito M, Shiro M, Hashimoto S,. (S)-3,3'-Dimethyl-2,2'- biquinoline N,N'-dioxide as an efficient catalyst for enantioselective addition of allyltrichlorosilanes to aldehydes. J Am Chem Soc 1998; 120: 6419-6420.
49. Ogawa C, Konishi H, Sugiura M, Kobayashi S,. Phosphine oxides as efficient neutral coordinate-organocatalysts for stereoselective allylation of N-acylhydrazones. Org Biomol Chem 2004; 2: 446-448.
50. Short JD, Attenoux S, Berrisford DJ,. Additive effects on ligand activated allylation of aldehydes by allyltrichlorosilane. Tetrahedron Lett 1997; 38: 2351-2354.
51. Chataigner I, Piarulli U, Gennari C,. Ureas: New efficient Lewis base catalysts for the allylation of aldehydes. Tetrahedron Lett 1999; 40: 3633-3634.
52. Wojaczyńska E, Wojaczyński J,. Enantioselective synthesis of sulfoxides: 2000-2009. Chem Rev 2010; 110: 4303-4356.
53. Carreño MC, Hernández-Torres G, Ribagorda M, Urbano A,. Enantiopure sulfoxides: recent applications in asymmetric synthesis. Chem Commun 2009; 6129-6144.
54. Fernández I, Khiar N,. Organosulfur chemistry in asymmetric synthesis Chap. 8. Weinheim, Germany: Wiley-VCH; 2008. p 265-290.
55. Hiroi K, Sone T,. Chiral sulfur ligands for catalytic asymmetric synthesis. Curr Org Synth 2008; 5: 305-320.
56. 2-Symmetric bis-sulfoxides as organocatalysts in the allylation of benzoyl hydrazones: spacer and concentration effects. Org Lett 2007; 9: 2215-2218.
57. Pellissier H,. Use of chiral sulfoxides in asymmetric synthesis. Tetrahedron 2006; 62: 5559-5601.
58. Senanayake CH, Krishnamurthy D, Lu ZH, Han Z, Gallou I,. Enantiopure sulfoxides and sulfinamides: recent developments in their stereoselective synthesis and applications to asymmetric synthesis. Aldrichim Acta 2005; 38: 93-104.
59. Fernández I, Khiar N,. Recent developments in the synthesis and utilization of chiral sulfoxides. Chem Rev 2003; 103: 3651-3705.
60. Carreño MC,. Applications of sulfoxides to asymmetric synthesis of biologically active compounds. Chem Rev 1995; 95: 1717-1760.
61. 2-symmetric chiral bis-sulfoxide ligand and its palladium(II) complex. Tetrahedron Lett 1995; 36: 8035-8038.
62. 2-Symmetric bis-sulfoxides as chiral ligands in metal catalysed asymmetric Diels-Alder reactions. Tetrahedron Lett 1993; 34: 123-126.
63. Walker AJ,. Asymmetric carbon-carbon bond formation using sulfoxide-stabilised carbanions. Tetrahedron: Asymmetry 1992; 3: 961-998.
64. Posner GH,. Asymmetric synthesis of carbon-carbon bonds using sulfinyl cycloalkenones, alkenolides, and pyrones. Acc Chem Res 1987; 20: 72-78.
65. Mikolajczyk M, Drabowicz J,. Topics in stereochemistry, Vol. 13. New York: Wiley; 1982. p. 333-468.
66. Solladié G,. Asymmetric synthesis using nucleophilic reagents containing a chiral sulfoxide group. Synthesis 1981; 185-196.
67. James BR, McMillan RS,. Catalytic asymmetric hydrogenation using ruthenium(II) complexes with chelating chiral sulfoxide ligands. Can J Chem 1977; 55: 3927-3932.
68. Zhang X, Chen J, Han F, Cun L, Liao J,. Rhodium-catalyzed enantioselective conjugate addition of sodium tetraarylborates to 2,3-dihydro-4-pyridones and 4-quinolones by using (R,R)-1,2-bis(tert- butylsulfinyl)benzene as a ligand. Eur J Org Chem 2011; 1443-1446.
69. 2-Symmetric chiral bis-sulfoxide ligand in a rhodium-catalyzed reaction: asymmetric 1,4-addition of sodium tetraarylborates to chromenones. J Am Chem Soc 2010; 132: 4552-4553.
70. 2-Symmetric chiral disulfoxide ligands in rhodium-catalyzed 1,4-addition: from ligand synthesis to the enantioselection pathway. Chem Eur J 2010; 16: 14335-14347.
71. Qi X, Rice GT, Lall MS, Plummer MS, White MC,. Diversification of a β-lactam pharmacophore via allylic C-H amination: accelerating effect of Lewis acid co-catalyst. Tetrahedron 2010; 66: 4816-4826.
72. Chen QA, Dong X, Chen MW, Wang DS, Zhou YG, Li YX,. Highly effective and diastereoselective synthesis of axially chiral bis-sulfoxide ligands via oxidative aryl coupling. Org Lett 2010; 12: 1928-1931.
73. Bürgi JJ, Mariz R, Gatti M, Drinkel E, Luan X, Blumentritt S, Linden A, Dorta R,. Unprecedented selectivity via electronic substrate recognition in the 1,4-addition to cyclic olefins using a chiral disulfoxide rhodium catalyst. Angew Chem Int Ed 2009; 48: 2768-2771.
74. Mariz R, Luan X, Gatti M, Linden A, Dorta R,. A chiral bis-sulfoxide ligand in late-transition metal catalysis; rhodium-catalyzed asymmetric addition of arylboronic acids to electron-deficient olefins. J Am Chem Soc 2008; 130: 2172-2173.
75. Young AJ, White MC,. Catalytic intermolecular allylic C-H alkylation. J Am Chem Soc 2008; 128: 14090-14091.
76. Chen MS, White MC,. A sulfoxide-promoted, catalytic method for the regioselective synthesis of allylic acetates from monosubstituted olefins via C-H oxidation. J Am Chem Soc 2004; 126: 1346-1347.
77. De Sio V, Massa A, Scettri A,. Chiral sulfoxides as activators of allyl trichlorosilanes in the stereoselective allylation of aldehydes. Org Biomol Chem 2010; 8: 3055-3059.
78. Fulton JR, Kamara LM, Morton SC, Rowlands GJ,. The sulfinyl moiety in Lewis base-promoted allylations. Tetrahedron 2009; 65: 9134-9141.
79. Wang P, Chen J, Cun L, Deng J, Zhu J, Liao J,. Aryl tert-butyl sulfoxide-promoted highly enantioselective addition of allyltrichlorosilane to aldehydes. Org Biomol Chem 2009; 7: 3741-3747.
80. 2-symmetric bis-sulfoxide organocatalysts. Tetrahedron Lett 2006; 47: 8235-8238 [Erratum: García-Flores F, Flores-Michel LS, Juaristi E, Tetrahedron Lett 2007;48:3315].
81. Melo RPA, Vale JA, Zeni G, Menezes PH,. Enantioselective allylation of aldehydes promoted by chiral sulfur reagents. Tetrahedron Lett 2006; 47: 1829-1831.
82. Fernández I, Valdivia V, Gori B, Alcudia F, Álvarez E, Khiar N,. The isopropylsulfinyl group: a useful chiral controller for the asymmetric aziridination of sulfinylimines and the organocatalytic allylation of hydrazones. Org Lett 2005; 7: 1307-1310.
83. Massa A, Malkov AV, Kočovský P, Scettri A,. Asymmetric allylation of aldehydes with allyltrichlorosilane promoted by chiral sulfoxides. Tetrahedron Lett 2003; 44: 7179-7181.
84. Rowlands GJ, Barnes WK,. Chiral sulfoxides in the enantioselective allylation of aldehydes with allyltrichlorosilane. Chem Commun 2003; 2712-2713.
85. 2-symmetric bis-sulfinamides as enhanced chiral organic promoters. Org Biomol Chem 2010; 8: 4388-4393.
86. Bai B, Shen L, Ren J, Zhu HJ,. Chiral biscarboline N,N'-dioxide derivatives: highly enantioselective addition of allyltrichlorosilane to aldehydes. Adv Synth Catal 2012; 354: 354-358.
87. Liu L, Zhang S, Xue F, Lou G, Zhang H, Ma S, Duan W, Wang W,. Catalytic enantioselective Henry reactions of isatins: application in the concise synthesis of (S)-(-)-spirobrassinin. Chem Eur J 2011; 17: 7791-7795.
88. Prathima PS, Srinivas K, Balaswamy K, Arundhathi R, Reddy GN, Sridhar B, Rao MM, Likhar PR,. Biscinchona alkaloid catalysed Henry reaction of isatins: enantioselective synthesis of 3-hydroxy-3-(nitromethyl)indolin-2-ones. Tetrahedron: Asymmetry 2011; 22: 2099-2103.
89. Bella M, Gasperi T,. Organocatalytic formation of quaternary stereocenters. Synthesis 2009; 1583-1614.
90. Riant O, Hannedouche J,. Asymmetric catalysis for the construction of quaternary carbon centres: nucleophilic addition on ketones and ketimines. Org Biomol Chem 2007; 5: 873-888.
91. Christoffers J, Baro A,. Stereoselective construction of quaternary stereocenters. Adv Synth Catal 2005; 347: 1473-1482.
92. Ramon DJ, Yus M,. Enantioselective synthesis of oxygen-, nitrogen- and halogen-substituted quaternary carbon centers. Curr Org Chem 2004; 8: 149-183.
93. Peterson EA, Overman LE,. Contiguous stereogenic quaternary carbons: a daunting challenge in natural products synthesis. Proc Natl Acad Sci USA 2004; 101: 11943-11948.
94. Betancort JM, Winn DT, Liu R, Xu Q, Liu J, Liao W, Chen SH, Carney D, Hanway D, Schmeits J, Li X, Gordon E, Campbell DA,. Bicyclic cyanothiazolidines as novel dipeptidyl peptidase 4 inhibitors. Bioorg Med Chem Lett 2009; 19: 4437-4440.
95. Savage SA, Waltermire RE, Campagna S, Bordawekar S, Riva Toma JD,. Development and large-scale preparation of an oral TACE inhibitor. Org Process Res Dev 2009; 13: 510-518.
96. Métro TX, Appenzeller J, Gomez Pardo D, Cossy J,. Highly enantioselective synthesis of β-amino alcohols. Org Lett 2006; 8: 3509-3512.
97. Maeda K, Miller RA, Szumigala RH, Shafiee A, Karady S, Armstrong JD,. Stereoselective synthesis of 4-hydroxy-2-phenylproline framework. Tetrahedron Lett 2005; 46: 1545-1549.
98. Abell AD, Gardiner J, Phillips AJ, Robinson WT,. Synthesis and X-ray structure of a 1,2,3,6-tetrahydropyridine-based phenylalanine mimetic. Tetrahedron Lett 1998; 39: 9563-9566.
99. Cativiela C, Díaz-de-Villegas MD,. Recent progress on the stereoselective synthesis of acyclic quaternary α-amino acids. Tetrahedron: Asymmetry 2007; 18: 569-623.
100. Vogt H, Bräse S,. Recent approaches towards the asymmetric synthesis of α,α-disubstituted α-amino acids. Org Biomol Chem 2007; 5: 406-430.
101. Ohfune Y, Shinada T,. Enantio- and diastereoselective construction of α,α-disubstituted α-amino acids for the synthesis of biologically active compounds. Eur J Org Chem 2005; 5127-5143.
102. Maruoka K, Ooi T,. Enantioselective amino acid synthesis by chiral phase-transfer catalysis. Chem Rev 2003; 103: 3013-3028.
103. Cativiela C, Díaz-de-Villegas MD,. Stereoselective synthesis of quaternary α-amino acids. Part 1: acyclic compounds. Tetrahedron: Asymmetry 1998; 9: 3517-3599.
104. Duthaler RO,. Recent developments in the stereoselective synthesis of α-aminoacids. Tetrahedron 1994; 50: 1539-1650.
105. 2-Schiff base complex for catalytic asymmetric synthesis of α-tetrasubstituted anti- α,β-diamino acid surrogates. J Am Chem Soc 2008; 130: 2170-2171.
106. Juaristi E, Soloshonok V, editors. Enantioselective synthesis of β-amino acids, 2nd ed. Hoboken, NJ: Wiley; 2005.
107. Knudsen KR, Jørgensen KA,. A chiral molecular recognition approach to the formation of optically active quaternary centres in aza-Henry reactions. Org Biomol Chem 2005; 3: 1362-1364.
108. Belokon YN, Bhave D, D'Addario D, Groaz E, North M, Tagliazucca V,. Copper(II)salen catalysed, asymmetric synthesis of α,α-disubstituted amino acids. Tetrahedron 2004; 60: 1849-1861.
109. Arboré APA, Cane-Honeysett DJ, Coldham I, Middleton ML,. A rapid approach to amino-acid derivatives by [2,3]-Stevens rearrangement. Synlett 2000; 236-238.
110. Wu HL, Wu PY, Shen YY, Uang BJ,. Asymmetric addition of dimethylzinc to α-ketoesters catalyzed by (-)-MITH. J Org Chem 2008; 73: 6445-6447.
111. Hu S, Neckers DC,. Photochemical reactions of alkyl phenylglyoxylates. J Org Chem 1996; 61: 6407-6415.
112. Berger R, Duff K, Leighton JL,. Enantioselective allylation of ketone-derived benzoylhydrazones: practical synthesis of tertiary carbinamines. J Am Chem Soc 2004; 126: 5686-5687.
113. 2 chiral diamine in aqueous media. Chem Eur J 2006; 12: 1205-1215.
114. Hartwig W, Schöllkopf U,. Asymmetrische Synthesen über Heterocyclische Zwischenstufen, XVI. Enantioselektive Synthese von α-Alkyl-α-phenylglycinen durch alkylieren von an C-6 Chiral Substituierten 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-onen. Liebigs Ann Chem 1982; 1952-1970.
115. Betsbrugge JV, Tourwé D, Kaptein B, Kierkels H, Broxterman R,. A convenient synthesis of protected (R)-α-phenylproline derivatives using the Mitsunobu reaction. Tetrahedron 1997; 53: 9233-9240.
116. Uraguchi D, Asai Y, Seto Y, Ooi T,. Asymmetric synthesis of α,α-disubstituted α-amino acids via enantioselective alkylation of azlactones under biphasic conditions using P-spiro chiral tetraaminophosphonium salts as a phase-transfer catalyst. Synlett 2009; 658-660.
117. Ooi T, Takeuchi M, Ohara D, Maruoka K,. Advantage of anaerobic conditions in the highly enantioselective synthesis of α,α-dialkyl-α- amino acids by chiral phase-transfer catalysis. Synlett 2001; 1185-1187.
118. Berova N, Di Bari L, Pescitelli G,. Application of electronic circular dichroism in configurational and conformational analysis of organic compounds. Chem Soc Rev 2007; 36: 914-931.
119. Li XC, Ferreira D, Ding Y,. Determination of absolute configuration of natural products: theoretical calculation of electronic circular dichroism as a tool. Curr Org Chem 2010; 14: 1678-1697.
120. Coriani S, Forzato C, Furlan G, Nitti P, Pitacco G, Ringholm M, Ruud K,. Synthesis, characterization and assignment of the absolute configuration of 4,4-dimethyl-5-oxo-tetrahydrofuran-3-carboxylic acid and its esters: a combined experimental and theoretical investigation. Tetrahedron: Asymmetry 2009; 20: 1459-1467.
121. Takayama H, Shimizu T, Sada H, Harada Y, Kitajima M, Aimi N,. Stereochemical studies on the Uncaria alkaloid, 3-oxo-7-hydroxy-3,7- secorhynchophylline: the absolute configuration of 3-hydroxyoxindole derivatives. Tetrahedron 1999; 55: 6841-6846.
122. Luppi G, Cozzi PG, Monari M, Kaptein B, Broxterman QB, Tomasini C,. Dipeptide-catalyzed asymmetric aldol condensation of acetone with (N-alkylated) isatins. J Org Chem 2005; 70: 7418-7421.
123. Nakamura T, Shirokawa S, Hosokawa S, Nakasaki A, Kobayashi S,. Enantioselective total synthesis of convolutamydines B and E. Org Lett 2006; 8: 677-679.
124. Nagai U, Kawai M, Yamada T, Kuwata S, Watanabe H,. A method for determining the absolute configuration of β-amino acids by CD spectra of their DNP derivatives. Tetrahedron Lett 1981; 22: 653-654.