Development of a New Chiral Spiro Oxazolinylpyridine Ligand (Spymox) for Asymmetric Catalysis

Abstract

A novel optically active 2-(oxazolinyl)pyridine ligand (Spymox) having a spiro binaphthyl backbone was synthesized from an α,α-disubstituted α-amino acid (H-Bin-OH), and successfully used in palladium-catalyzed asymmetric allylic alkylations to afford the corresponding alkylated products with 99% ee.

Development of new chiral ligands for asymmetric synthesis is an important research subject in synthetic organic chemistry. Recently, optically active spiro compounds have attracted significant attention as a new class of chiral ligands because their rigid spiro structure can result in a fairly rigid transition-state geometry during the course of asymmetric metal catalysis. [¹] However, there are few reports on the successful development of spiro chiral ligands, especially which have spiro structure on their side arm, because of the difficulty involved in the preparation of these ligands in optically pure form. [²] [³] Herein, we have designed chiral spiro 2-(oxazolinyl)pyridine (Spymox) as a novel N,N-bidentate ligand. [4] Spymox was efficiently synthesized from 2-picolinic acid and H-Bin-OR, [5] which is an α,α-disubstituted α-amino acid with an axial chiral binaphthyl backbone (Scheme  [¹] ). Surprisingly, no report have been appeared on the application of this unique artificial amino acid to asymmetric catalysis, though chiral α-amino acids have been frequently used as synthons for numerous chiral ligands [6] and organocatalysts. [7] In this paper, we discuss the concise synthesis of spymox and its successful application to palladium-catalyzed asymmetric allylic alkylations. [8]

The synthesis of Spymox (1) is shown in Scheme  [²] . H-[(R)-Bin]-OEt (3) was synthesized from (R)-2,2′-bis(bromomethyl)-1,1′-binaphthyl (2) and ethyl isocyanoacetate using a phase-transfer catalyst in 84% yield. This procedure is much more concise than the previous report using glycine tert-butyl ester Schiff base. [5] The amido alcohol 4 was obtained by the condensation of 3 with 2-picolinoyl chloride, followed by reduction of the ethyl ester with LiBH₄. After chlorination of the primary alcohol with SOCl₂, the oxazoline ring was formed under basic conditions to afford (R)-1 with 45% yield (25% overall yield).

The asymmetric induction of Spymox was evaluated by using it in the palladium-catalyzed asymmetric alkylation of racemic 1,3-diphenyl-2-propenyl acetate (5a). [9] Fortunately, the palladium complex of (R)-1 catalyzed the alkylation of 5a with dimethyl malonate to afford the desired product 6a with 99% ee. As sumarized in Table  [¹] , excellent enantioselectivities were observed in a variety of solvents, including highly polar solvents and protic solvents. Notably, the use of tert-butyl methyl ether (TBME) as the solvent resulted in a dramatic enhancement of the catalytic activity to afford 6a in a high yield, even at ambient temperature (entry 7). Moderate enantioselectivities were observed when monosubstituted 2-(oxazolinyl)pyridine ligands (pymox) were used in the same reaction (entries 8 and 9). [¹0] These results clearly show that our ligand with a spiro bicyclic oxazoline backbone is very advantageous for asymmetric induction.

Table 1 Asymmetric Allylic Alkylation of 5a with Dimethyl Malonate Catalyzed by Pd-Spymox Complex^a

Entry	Solvent	Ligand	Yield (%)b	ee (%)c
1	CH2Cl2	(R)-1	29	99 (R)
2	THF	(R)-1	29	99 (R)
3	i-PrOH	(R)-1	26	99 (R)
4	DMF	(R)-1	15	99 (R)
5	toluene	(R)-1	23	99 (R)
6d	toluene	(R)-1	91	99 (R)
7	TBME	(R)-1	90	99 (R)
8	TBME	(S)-pymox-Bn	65	14 (S)
9e	TBME	(S)-pymox-Ph	15	45 (S)
a All reactions were carried out with 2 equiv of dimethyl malonate and 1 equiv of K2CO3 in the presence of palladium complex prepared from ligand (12 mol%) and [Pd(η³-C3H5)Cl]2 (5 mol%). b Isolated yield. c Determined by HPLC analyses. d The reaction run at 80 ˚C. e The reaction run for 48 h.

Next, the scope of the substrate was expanded to various substituted 1,3-diphenyl-2-propenyl acetates. As shown in Table  [²] , excellent enantioselectivities (97-99% ee) were observed in all the examples, though substrates possessing electron-withdrawing or electron-donating groups required high temperatures or the use of NaH as a base to facilitate a high rate of conversion.

Table 2 Asymmetric Allylic Alkylation of Various 1,3-Diaryl-2-propenyl Acetates^a

Entry	Substrate	Temp (˚C)	Yield (%)b	ee (%)c
1	5a	r.t.	90	99 (R)
2	5b	r.t.	<5	n.d.
3	5b	55	<5	n.d.
4d	5b	55	84	99
5	5c	r.t.	27	99
6	5c	55	92	99
7	5d	r.t.	30	97
8	5d	55	73	97
9	5e	55	94	98
a All reactions were carried out with 2 equiv of dimethyl malonate and 1 equiv of K2CO3 in the presence of palladium complex prepared from (R)-1 (12 mol%) and [Pd(η³-C3H5)Cl]2 (5 mol%) unless otherwise noted. b Isolated yield. c Determined by HPLC analysis. d NaH (1 equiv) was used instead of K2CO3.

Finally, we tested several malonates (7a-e) as nucleophiles (Table  [³] ). The reactions of 5a with dialkyl malonates 7a,b proceeded smoothly to afford the desired products 8a,b with 98-99% ee (entries 1 and 2). The use of α-substituted malonates, including the α-fluorinated malonate 7d, [¹¹] also afforded the corresponding allylated products 8c,d with excellent enantioselectivities (entries 3 and 4).

Table 3 Asymmetric Allylic Alkylation of 5a with Various Malonates^a

Entry	Nucleophile	Temp (˚C)	Time (h)	Yield (%)b	ee (%)c
1	7a	55	24	82	>99 (R)
2	7b	55	14	90	>99
3	7c	55	14	94	99 (S)
4	7d	rt	48	58	>99
a All reactions were carried out with 2 equiv of dimethyl malonate and 2 equiv of K2CO3 in the presence of palladium complex prepared from (R)-1 (12 mol%) and [Pd(η³-C3H5)Cl]2 (5 mol%). b Isolated yield. c Determined by HPLC analysis.

A plausible transition-state model is proposed in Figure  [¹] . One of naphthyl rings on the ligand shields the upper right-hand side of the π-allyl palladium complex; thus, the position of nucleophilic attack as well as the formation of the π-allyl complex (two phenyl groups would be located below) are properly controlled.

In conclusion, we have synthesized a novel optically active spiro ligand from H-Bin-OH; this has been successfully applied to palladium-catalyzed asymmetric allylic alkylations. To the best of our knowledge, this is the first example of the use of H-Bin-OH derivatives for asym­metric catalysis. Further study on the application of H-Bin-OH and its derivatives to the preparation of novel chiral catalysts are under way.

Typical Procedure for Asymmetric Allylic Alkylations

A flame-dried flask under argon was charged with (R)-1 (0.024 mmol) and [Pd(η^³-C₃H₅)Cl]₂ (0.01 mmol). Dichloromethane (1 mL) was added to this mixture. After the reaction mixture was stirred for 1 h at r.t., CH₂Cl₂ was evaporated in vacuo. Residual Pd complex was dissolved into TBME (5 mL). 1,3-Diphenyl-2-propenyl acetate (5a, 0.2 mmol), dimethyl malonate (0.4 mmol), and K₂CO₃ (0.4 mmol) were added to this solution. The reaction mixture was stirred for 14 h at r.t. The reaction was quenched with sat. aq NH₄Cl, and the mixture was extracted by CH₂Cl₂. The organic layer was dried over Na₂SO₄, concentrated, and chromatographed on SiO₂ to give 6a in 90%yield with 99% ee.

Products 6a-d and 8a-d were identical in all respects to the known literature compounds. [¹²-¹5]

See the references section for analytical details of new compounds 1, 4, 5e, and 6e. [¹6-¹9]

CAS Registry Numbers

5a: 73930-97-9; 5b: 881397-70-2; 5c: 195192-51-9; 5d: 881397-68-8; pymox-Ph: 153880-57-0; pymox-Bn: 108915-08-8; 7d: 344-14-9.

Acknowledgment

This study was supported by a Grant-in-Aid for Scientific Research (C) (No. 20550137) from Japan Society for the Promotion of Science. We thank The Nippon Synthetic Chemical Industry Co., Ltd. for supplying ethyl isocyanoacetate used in this study.

References and Notes

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  CrossrefSearch in Google Scholar
• Most of the reported efficient spiro chiral ligands have a 1,1′-spirobiindane backbone. For examples, see:
• 2a Birman VB. Rheingold AL. Lam K.-C. Tetrahedron: Asymmetry  1999,  10:  125 
  Search in Google Scholar
• 2b Hu A.-G. Fu Y. Xie J.-H. Zhou H. Wang L.-X. Zhou Q.-L. Angew. Chem. Int. Ed.  2002,  41:  2348 
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• 2d Xie J.-H. Duan H.-F. Fan B.-M. Cheng X. Wang L.-X. Zhou Q.-L. Adv. Synth. Catal.  2004,  346:  625 
  Search in Google Scholar
• 2e Zhu S.-F. Yang Y. Wang L.-X. Liu B. Zhou Q.-L. Org. Lett.  2005,  7:  2333 
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• 2f Cheng X. Zhang Q. Xie J.-H. Wang L.-X. Zhou Q.-L. Angew. Chem. Int. Ed.  2005,  44:  1118 
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• 2g Zhu S.-F. Xie J.-B. Zhang Y.-Z. Li S. Zhou Q.-L. J. Am. Chem. Soc.  2006,  128:  12886 
  Search in Google Scholar
• 2h Chen C. Zhu S.-F. Liu B. Wang L.-X. Zhou Q.-L. J. Am. Chem. Soc.  2007,  129:  12616 
  Search in Google Scholar
• Examples of spiro chiral ligands other than those listed in ref. 2:
• 3a Jiang Y. Mi A. Yan M. Sun J. Lou R. Deng J. J. Am. Chem. Soc.  1997,  119:  9570 
  Search in Google Scholar
• 3b Arai MA. Arai T. Sasai H. Org. Lett.  1999,  1:  1795 
  Search in Google Scholar
• 3c Arai MA. Kuraishi M. Arai T. Sasai H. J. Am. Chem. Soc.  2001,  123:  2907 
  Search in Google Scholar
• 3d Wu S.-L. Zhang W.-C. Zhang Z.-G. Zhang X.-M. Org. Lett.  2004,  6:  3565 
  Search in Google Scholar
• 3e Lin CW. Lin C.-C. Lam LF.-L. Au-Yeung TT.-L. Chan ASC. Tetrahedron Lett.  2004,  45:  7379 
  Search in Google Scholar
• 3f Lait SM. Parvez M. Keay BA. Tetrahedron: Asymmetry  2004,  15:  155 
  Search in Google Scholar
• 3g Guo Z. Guan X. Chen Z. Tetrahedron: Asymmetry  2006,  17:  468 
  Search in Google Scholar
• 3h Koranne PS. Tsujihara T. Arai MA. Bajracharya GB. Suzuki T. Onitsuka K. Sasai H. Tetrahedron: Asymmetry  2007,  18:  919 
  Search in Google Scholar
• Recent reviews on nitrogen-containing chiral ligands:
• 4a Fache F. Schulz E. Tommasino ML. Lemaire M. Chem. Rev.  2000,  100:  2159 
  Search in Google Scholar
• 4b McManus HA. Guiry PJ. Chem. Rev.  2004,  104:  4151 
  Search in Google Scholar
• Synthesis of H-Bin-OR and their application to peptide chemistry:
• 5a Mazaleyrat J.-P. Gaucher A. Wakselman M. Tchertanov L. Guilhem J. Tetrahedron Lett.  1996,  37:  2971 
  Search in Google Scholar
• 5b Mazaleyrat J.-P. avrda J. Wakselman M. Tetrahedron: Asymmetry  1997,  8:  619 
  Search in Google Scholar
• 5c Mazaleyrat J.-P. Boutboul A. Lebars Y. Gaucher A. Wakselman M. Tetrahedron: Asymmetry  1998,  9:  2701 
  Search in Google Scholar
• 5d Mazaleyrat J.-P. Wright K. Gaucher A. Wakselman M. Oancea S. Formaggio F. Toniolo C. Setnika V. Kapitán J. Keiderling TA. Tetrahedron: Asymmetry  2003,  14:  1879 
  Search in Google Scholar
• 6a Catalytic Asymmetric Synthesis   2nd ed.:  Ojima I. Wiley-VCH; New York: 2000. 
• 6b Comprehensive Asymmetric Catalysis   Vol. 1-3:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 1999. 
• 7a Dalko PI. Moisan L. Angew. Chem. Int. Ed.  2004,  43:  5138 
  Search in Google Scholar
• 7b Berkessel A. Gröger H. Asymmetric Organocatalysis   Wiley-VCH; Weinheim: 2005. 
• 7c Enantioselective Organocatalysis: Reactions and Experimental Procedures   Dalko PI. Wiley-VCH; Weinheim: 2007. 
• Reviews on the asymmetric allylic alkylation reaction:
• 8a Paquin J.-F. Lautens M. In Comprehensive Asymmetric Catalysis   Suppl. 2:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; Berlin: 2004.  p.73-95  ; and references therein
  Search in Google Scholar
• 8b Pfaltz A. Lautens M. In Comprehensive Asymmetric Catalysis   Vol. 2:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 1999.  p.833-884  ; and references therein
  Search in Google Scholar
• Palladium-catalyzed asymmetric allylic alkylations with fluorinated carbanion:
• 11a Fukuzumi T. Shibata N. Sugiura M. Yasui H. Nakamura S. Toru T. Angew. Chem. Int. Ed.  2006,  45:  4973 
  Search in Google Scholar
• 11b Jiang B. Huang Z.-G. Cheng K.-J. Tetrahedron: Asymmetry  2006,  17:  942 
  Search in Google Scholar
• 11c Zhang F. Song ZJ. Tschaen D. Volante RP. Org. Lett.  2004,  6:  3775 
  Search in Google Scholar
• 11d Komatsu Y. Sakamoto T. Kitazume T. J. Org. Chem.  1999,  64:  8369 
  Search in Google Scholar
• 12 For compounds 6a, 8c, see: Imamoto T. Nishimura M. Koide A. Yoshida K. J. Org. Chem.  2007,  72:  7413 
  CrossrefSearch in Google Scholar
• 13 For compounds 6b-d, 8b, see: Kinoshita N. Kawabata T. Tsubaki K. Bando M. Fuji K. Tetrahedron  2006,  62:  1756 
  CrossrefSearch in Google Scholar
• 14 For compound 8a, see: Braga AL. Vargas F. Sehnem JA. Braga RC. J. Org. Chem.  2005,  70:  9021 
  CrossrefSearch in Google Scholar
• 15 For compound 8d, see: Jiang B. Huang Z.-G. Cheng K.-J. Tetrahedron: Asymmetry  2006,  17:  942 
  CrossrefSearch in Google Scholar

Palladium-catalyzed asymmetric allylic alkylation using a spiro chiral ligand having a 1,1′-spirobiindane backbone (SDP) has been reported, see ref. [²d] .

A previous report on asymmetric allylic alkylation using pymox-Pd complex also shows moderate enantioselectivity (50% ee): Nordström K., Macedo E., Moberg C.; J. Org. Chem.; 1997, 62: 1604

Compound 1: ^¹H NMR (300 MHz, CDCl₃): δ = 8.71 (m, 1 H), 8.08 (m, 1 H), 7.95 (m, 4 H), 7.77 (m, 1 H), 7.65 (d, J = 8.0 Hz, 1 H), 7.50 (d, J = 8.4 Hz, 1 H), 7.46-7.38 (m, 4 H), 7.33 (d, J = 8.8 Hz, 1 H), 7.27-7.20 (m, 2 H), 4.65 (d, J = 8.8 Hz, 1 H), 3.95 (d, J = 8.8 Hz, 1 H), 2.94 (d, J = 13.1 Hz, 1 H), 2.88 (d, J = 13.3 Hz, 1 H), 2.72 (d, J = 13.3 Hz, 1 H), 2.65 (d, J = 13.1 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 162.1, 149.8, 147.0, 136.7, 135.4, 134.7, 134.5, 133.7, 133.1, 133.0, 132.1, 131.9, 128.7, 128.5, 128.4, 128.4, 128.3, 127.5, 127.4, 127.2, 126.0, 125.7, 125.4, 125.1, 124.4, 82.5, 77.3, 44.4, 43.5. IR (neat): 3847, 3741, 3475, 3053, 2938, 1635, 1577, 1469, 1361, 1302, 1092, 968, 813, 751, 696, 615 cm^-¹. Anal. Calcd (%) for C₃₀H₂₂N₂O: C, 84.48; H, 5.20; N, 6.57. Found: C, 84.67; H, 5.15; N, 6.36. [α]_D -72.4 (c 1.25, CHCl₃).

Compound 4: ^¹H NMR (300 MHz, CDCl₃): δ = 8.45 (m, 1 H), 8.23 (m, 2 H), 7.96-7.86 (m, 5 H), 7.55 (m, 1 H), 7.48-7.37 (m, 6 H), 7.29-7.23 (m, 2 H), 5.19 (dd, J = 5.2, 8.0 Hz, 1 H), 4.01 (dd, J = 8.0, 11.5 Hz, 1 H), 3.83 (dd, J = 5.2, 11.5 Hz, 1 H), 3.23 (d, J = 13.7 Hz, 1 H), 3.11 (d, J = 12.4 Hz, 1 H), 2.54 (d, J = 13.7 Hz, 1 H), 2.45 (d, J = 12.4 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 165.0, 149.6, 148.2, 137.8, 135.4, 135.4, 134.8, 134.6, 134.4, 133.2, 133.2, 133.1, 132.0, 132.0, 128.6, 128.4, 128.4, 128.1, 128.1, 127.4, 126.6, 126.1, 126.0, 125.6, 125.4, 122.3, 70.2, 66.9, 41.0, 38.9. IR (neat): 3846, 3343, 3053, 2928, 1667, 1525, 1457, 1324, 1245, 1058, 817, 752, 697, 621, 436 cm^-¹. Anal. Calcd (%) for C₃₀H₂₄N₂O₂: C, 80.06; H, 5.44; N, 6.30. Found: C, 81.34; H, 5.74; N, 6.03. [α]_D -90.5 (c 1.0, CHCl₃).

Compound 5e: ^¹H NMR (300 MHz, CDCl₃): δ = 7.29-7.05 (m, 8 H), 6.60 (d, J = 15.3 Hz, 1 H), 6.41-6.28 (m, 2 H), 2.36 (s, 3 H), 2.32 (s, 3 H), 2.13 (s, 3 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 170.2, 139.3, 138.4, 138.2, 136.2, 132.6, 129.0, 128.9, 128.63, 128.57, 127.8, 127.5, 124.2, 124.0, 76.4, 21.6, 21.49, 21.45. Anal. Calcd (%) for C₁₉H₂₀O₂: C, 81.40; H, 7.19; O, 11.41. Found: C, 81.06; H, 6.62.

Compound 6e: ^¹H NMR (300 MHz, CDCl₃): δ = 7.26-7.00 (m, 8 H), 6.44 (d, J = 15.6 Hz, 1 H), 6.29 (dd, J = 15.6 Hz, 1 H), 4.21 (dd, J = 10.8, 8.4 Hz, 1 H), 3.94 (d, J = 10.8 Hz, 1 H), 3.70 (s, 3 H), 3.53 (s, 3 H), 2.33 (s, 3 H), 2.31 (s, 3 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 168.4, 168.0, 140.3, 138.4, 138.1, 136.9, 131.9, 129.1, 128.7, 128.5, 128.0, 127.2, 124.8, 123.7, 57.7, 52.76, 52.74, 52.60, 52.57, 49.3. Anal. Calcd (%) for C₂₂H₂₄O₄: C, 74.98; H, 6.86; O, 18.16. Found: C, 74.69; H, 6.86. [α]_D +24.1 (c 0.63, CHCl₃). The er was determined by HPLC [hexane-2-PrOH (96:4), 0.5 mL/min] using a CHIRALPAK AD column (0.46 cm × 25 cm): t _R (major isomer) = 23.0 min; t _R (minor isomer) = 26.5 min.

References and Notes

• 1 A recent review for chiral phosphine ligands on a spiro scaffold: Xie J.-H. Zhou Q.-L. Acc. Chem. Res.  2008,  41:  581 
  CrossrefSearch in Google Scholar
• Most of the reported efficient spiro chiral ligands have a 1,1′-spirobiindane backbone. For examples, see:
• 2a Birman VB. Rheingold AL. Lam K.-C. Tetrahedron: Asymmetry  1999,  10:  125 
  Search in Google Scholar
• 2b Hu A.-G. Fu Y. Xie J.-H. Zhou H. Wang L.-X. Zhou Q.-L. Angew. Chem. Int. Ed.  2002,  41:  2348 
  Search in Google Scholar
• 2c Xie J.-H. Wang L.-X. Fu Y. Zhu S.-F. Fan B.-M. Duan H.-F. Zhou Q.-L. J. Am. Chem. Soc.  2003,  125:  4404 
  Search in Google Scholar
• 2d Xie J.-H. Duan H.-F. Fan B.-M. Cheng X. Wang L.-X. Zhou Q.-L. Adv. Synth. Catal.  2004,  346:  625 
  Search in Google Scholar
• 2e Zhu S.-F. Yang Y. Wang L.-X. Liu B. Zhou Q.-L. Org. Lett.  2005,  7:  2333 
  Search in Google Scholar
• 2f Cheng X. Zhang Q. Xie J.-H. Wang L.-X. Zhou Q.-L. Angew. Chem. Int. Ed.  2005,  44:  1118 
  Search in Google Scholar
• 2g Zhu S.-F. Xie J.-B. Zhang Y.-Z. Li S. Zhou Q.-L. J. Am. Chem. Soc.  2006,  128:  12886 
  Search in Google Scholar
• 2h Chen C. Zhu S.-F. Liu B. Wang L.-X. Zhou Q.-L. J. Am. Chem. Soc.  2007,  129:  12616 
  Search in Google Scholar
• Examples of spiro chiral ligands other than those listed in ref. 2:
• 3a Jiang Y. Mi A. Yan M. Sun J. Lou R. Deng J. J. Am. Chem. Soc.  1997,  119:  9570 
  Search in Google Scholar
• 3b Arai MA. Arai T. Sasai H. Org. Lett.  1999,  1:  1795 
  Search in Google Scholar
• 3c Arai MA. Kuraishi M. Arai T. Sasai H. J. Am. Chem. Soc.  2001,  123:  2907 
  Search in Google Scholar
• 3d Wu S.-L. Zhang W.-C. Zhang Z.-G. Zhang X.-M. Org. Lett.  2004,  6:  3565 
  Search in Google Scholar
• 3e Lin CW. Lin C.-C. Lam LF.-L. Au-Yeung TT.-L. Chan ASC. Tetrahedron Lett.  2004,  45:  7379 
  Search in Google Scholar
• 3f Lait SM. Parvez M. Keay BA. Tetrahedron: Asymmetry  2004,  15:  155 
  Search in Google Scholar
• 3g Guo Z. Guan X. Chen Z. Tetrahedron: Asymmetry  2006,  17:  468 
  Search in Google Scholar
• 3h Koranne PS. Tsujihara T. Arai MA. Bajracharya GB. Suzuki T. Onitsuka K. Sasai H. Tetrahedron: Asymmetry  2007,  18:  919 
  Search in Google Scholar
• Recent reviews on nitrogen-containing chiral ligands:
• 4a Fache F. Schulz E. Tommasino ML. Lemaire M. Chem. Rev.  2000,  100:  2159 
  Search in Google Scholar
• 4b McManus HA. Guiry PJ. Chem. Rev.  2004,  104:  4151 
  Search in Google Scholar
• Synthesis of H-Bin-OR and their application to peptide chemistry:
• 5a Mazaleyrat J.-P. Gaucher A. Wakselman M. Tchertanov L. Guilhem J. Tetrahedron Lett.  1996,  37:  2971 
  Search in Google Scholar
• 5b Mazaleyrat J.-P. avrda J. Wakselman M. Tetrahedron: Asymmetry  1997,  8:  619 
  Search in Google Scholar
• 5c Mazaleyrat J.-P. Boutboul A. Lebars Y. Gaucher A. Wakselman M. Tetrahedron: Asymmetry  1998,  9:  2701 
  Search in Google Scholar
• 5d Mazaleyrat J.-P. Wright K. Gaucher A. Wakselman M. Oancea S. Formaggio F. Toniolo C. Setnika V. Kapitán J. Keiderling TA. Tetrahedron: Asymmetry  2003,  14:  1879 
  Search in Google Scholar
• 6a Catalytic Asymmetric Synthesis   2nd ed.:  Ojima I. Wiley-VCH; New York: 2000. 
• 6b Comprehensive Asymmetric Catalysis   Vol. 1-3:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 1999. 
• 7a Dalko PI. Moisan L. Angew. Chem. Int. Ed.  2004,  43:  5138 
  Search in Google Scholar
• 7b Berkessel A. Gröger H. Asymmetric Organocatalysis   Wiley-VCH; Weinheim: 2005. 
• 7c Enantioselective Organocatalysis: Reactions and Experimental Procedures   Dalko PI. Wiley-VCH; Weinheim: 2007. 
• Reviews on the asymmetric allylic alkylation reaction:
• 8a Paquin J.-F. Lautens M. In Comprehensive Asymmetric Catalysis   Suppl. 2:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; Berlin: 2004.  p.73-95  ; and references therein
  Search in Google Scholar
• 8b Pfaltz A. Lautens M. In Comprehensive Asymmetric Catalysis   Vol. 2:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 1999.  p.833-884  ; and references therein
  Search in Google Scholar
• Palladium-catalyzed asymmetric allylic alkylations with fluorinated carbanion:
• 11a Fukuzumi T. Shibata N. Sugiura M. Yasui H. Nakamura S. Toru T. Angew. Chem. Int. Ed.  2006,  45:  4973 
  Search in Google Scholar
• 11b Jiang B. Huang Z.-G. Cheng K.-J. Tetrahedron: Asymmetry  2006,  17:  942 
  Search in Google Scholar
• 11c Zhang F. Song ZJ. Tschaen D. Volante RP. Org. Lett.  2004,  6:  3775 
  Search in Google Scholar
• 11d Komatsu Y. Sakamoto T. Kitazume T. J. Org. Chem.  1999,  64:  8369 
  Search in Google Scholar
• 12 For compounds 6a, 8c, see: Imamoto T. Nishimura M. Koide A. Yoshida K. J. Org. Chem.  2007,  72:  7413 
  CrossrefSearch in Google Scholar
• 13 For compounds 6b-d, 8b, see: Kinoshita N. Kawabata T. Tsubaki K. Bando M. Fuji K. Tetrahedron  2006,  62:  1756 
  CrossrefSearch in Google Scholar
• 14 For compound 8a, see: Braga AL. Vargas F. Sehnem JA. Braga RC. J. Org. Chem.  2005,  70:  9021 
  CrossrefSearch in Google Scholar
• 15 For compound 8d, see: Jiang B. Huang Z.-G. Cheng K.-J. Tetrahedron: Asymmetry  2006,  17:  942 
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Palladium-catalyzed asymmetric allylic alkylation using a spiro chiral ligand having a 1,1′-spirobiindane backbone (SDP) has been reported, see ref. [²d] .

A previous report on asymmetric allylic alkylation using pymox-Pd complex also shows moderate enantioselectivity (50% ee): Nordström K., Macedo E., Moberg C.; J. Org. Chem.; 1997, 62: 1604

Compound 1: ^¹H NMR (300 MHz, CDCl₃): δ = 8.71 (m, 1 H), 8.08 (m, 1 H), 7.95 (m, 4 H), 7.77 (m, 1 H), 7.65 (d, J = 8.0 Hz, 1 H), 7.50 (d, J = 8.4 Hz, 1 H), 7.46-7.38 (m, 4 H), 7.33 (d, J = 8.8 Hz, 1 H), 7.27-7.20 (m, 2 H), 4.65 (d, J = 8.8 Hz, 1 H), 3.95 (d, J = 8.8 Hz, 1 H), 2.94 (d, J = 13.1 Hz, 1 H), 2.88 (d, J = 13.3 Hz, 1 H), 2.72 (d, J = 13.3 Hz, 1 H), 2.65 (d, J = 13.1 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 162.1, 149.8, 147.0, 136.7, 135.4, 134.7, 134.5, 133.7, 133.1, 133.0, 132.1, 131.9, 128.7, 128.5, 128.4, 128.4, 128.3, 127.5, 127.4, 127.2, 126.0, 125.7, 125.4, 125.1, 124.4, 82.5, 77.3, 44.4, 43.5. IR (neat): 3847, 3741, 3475, 3053, 2938, 1635, 1577, 1469, 1361, 1302, 1092, 968, 813, 751, 696, 615 cm^-¹. Anal. Calcd (%) for C₃₀H₂₂N₂O: C, 84.48; H, 5.20; N, 6.57. Found: C, 84.67; H, 5.15; N, 6.36. [α]_D -72.4 (c 1.25, CHCl₃).

Compound 4: ^¹H NMR (300 MHz, CDCl₃): δ = 8.45 (m, 1 H), 8.23 (m, 2 H), 7.96-7.86 (m, 5 H), 7.55 (m, 1 H), 7.48-7.37 (m, 6 H), 7.29-7.23 (m, 2 H), 5.19 (dd, J = 5.2, 8.0 Hz, 1 H), 4.01 (dd, J = 8.0, 11.5 Hz, 1 H), 3.83 (dd, J = 5.2, 11.5 Hz, 1 H), 3.23 (d, J = 13.7 Hz, 1 H), 3.11 (d, J = 12.4 Hz, 1 H), 2.54 (d, J = 13.7 Hz, 1 H), 2.45 (d, J = 12.4 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 165.0, 149.6, 148.2, 137.8, 135.4, 135.4, 134.8, 134.6, 134.4, 133.2, 133.2, 133.1, 132.0, 132.0, 128.6, 128.4, 128.4, 128.1, 128.1, 127.4, 126.6, 126.1, 126.0, 125.6, 125.4, 122.3, 70.2, 66.9, 41.0, 38.9. IR (neat): 3846, 3343, 3053, 2928, 1667, 1525, 1457, 1324, 1245, 1058, 817, 752, 697, 621, 436 cm^-¹. Anal. Calcd (%) for C₃₀H₂₄N₂O₂: C, 80.06; H, 5.44; N, 6.30. Found: C, 81.34; H, 5.74; N, 6.03. [α]_D -90.5 (c 1.0, CHCl₃).

Compound 5e: ^¹H NMR (300 MHz, CDCl₃): δ = 7.29-7.05 (m, 8 H), 6.60 (d, J = 15.3 Hz, 1 H), 6.41-6.28 (m, 2 H), 2.36 (s, 3 H), 2.32 (s, 3 H), 2.13 (s, 3 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 170.2, 139.3, 138.4, 138.2, 136.2, 132.6, 129.0, 128.9, 128.63, 128.57, 127.8, 127.5, 124.2, 124.0, 76.4, 21.6, 21.49, 21.45. Anal. Calcd (%) for C₁₉H₂₀O₂: C, 81.40; H, 7.19; O, 11.41. Found: C, 81.06; H, 6.62.

Compound 6e: ^¹H NMR (300 MHz, CDCl₃): δ = 7.26-7.00 (m, 8 H), 6.44 (d, J = 15.6 Hz, 1 H), 6.29 (dd, J = 15.6 Hz, 1 H), 4.21 (dd, J = 10.8, 8.4 Hz, 1 H), 3.94 (d, J = 10.8 Hz, 1 H), 3.70 (s, 3 H), 3.53 (s, 3 H), 2.33 (s, 3 H), 2.31 (s, 3 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 168.4, 168.0, 140.3, 138.4, 138.1, 136.9, 131.9, 129.1, 128.7, 128.5, 128.0, 127.2, 124.8, 123.7, 57.7, 52.76, 52.74, 52.60, 52.57, 49.3. Anal. Calcd (%) for C₂₂H₂₄O₄: C, 74.98; H, 6.86; O, 18.16. Found: C, 74.69; H, 6.86. [α]_D +24.1 (c 0.63, CHCl₃). The er was determined by HPLC [hexane-2-PrOH (96:4), 0.5 mL/min] using a CHIRALPAK AD column (0.46 cm × 25 cm): t _R (major isomer) = 23.0 min; t _R (minor isomer) = 26.5 min.