Catalytic Enantioselective
Friedel-Crafts Alkylation of Indoles with β,γ-Unsaturated α-Keto
Phosphonates in the Presence of Chiral Palladium Complexes

Young Ku Kang; Ki Hyung Suh; Dae Young Kim

doi:10.1055/s-0030-1259932

LETTER

Catalytic Enantioselective Friedel-Crafts Alkylation of Indoles with β,γ-Unsaturated α-Keto Phosphonates in the Presence of Chiral Palladium Complexes

Young Ku Kang, Ki Hyung Suh, Dae Young Kim*
Department of Chemistry, Soonchunhyang University, Asan, Chungnam 336-745, Korea
Fax: +82(41)5301247; e-Mail: dyoung@sch.ac.kr;

Abstract

All articles of this category

Abstract

The catalytic enantioselective Friedel-Crafts alkylation reaction promoted by chiral palladium complexes is described. The treatment of indoles with β,γ-unsaturated α-keto phosphonates under the mild reaction conditions afforded the corresponding Friedel-Crafts alkylation adducts with excellent enantioselectivities (up to 99% ee).

Key words

Friedel-Crafts reaction - asymmetric catalysis - chiral palladium catalysts - indoles - β,γ-unsaturated α-keto phosphonates

Full Text

References

References and Notes

For reviews on Friedel-Crafts Alkylation, see:

<A NAME="RU00811ST-1A">1a</A> Jørgensen KA. Synthesis 2003, 1117

<A NAME="RU00811ST-1B">1b</A> Bandini M. Melloni A. Umani-Ronchi A. Angew. Chem. Int. Ed. 2004, 43: 550

<A NAME="RU00811ST-1C">1c</A> Bandini M. Melloni A. Tommasi S. Umani-Ronchi A. Synlett 2005, 1199

<A NAME="RU00811ST-1D">1d</A> Poulsen TB. Jørgensen KA. Chem. Rev. 2008, 108: 2903

<A NAME="RU00811ST-1E">1e</A> Tsogoeva SB. Eur. J. Org. Chem. 2007, 1701

<A NAME="RU00811ST-1F">1f</A> You S.-L. Cai Q. Zeng M. Chem. Soc. Rev. 2009, 38: 210

<A NAME="RU00811ST-1G">1g</A> Bandini M. Umani-Ronchi A. Catalytic Asymmetric Friedel-Crafts Alkylations Wiley-VCH; Weinheim: 2009.

<A NAME="RU00811ST-1H">1h</A> Zeng M. You S.-L. Synlett 2010, 1289

<A NAME="RU00811ST-1I">1i</A> Terrasson V. de Figueiredo RM. Campagne JM. Eur. J. Org. Chem. 2010, 2635

<A NAME="RU00811ST-2A">2a</A> Sundberg RJ. Indoles Academic Press; San Diego: 1996.

<A NAME="RU00811ST-2B">2b</A> Toyota M. Ihara M. Nat. Prod. Rep. 1998, 15: 327

<A NAME="RU00811ST-2C">2c</A> Huber U. Moore RE. Patterson GML. J. Nat. Prod. 1998, 61: 1304

<A NAME="RU00811ST-2D">2d</A> Kinsman AC. Kerr MA.
J. Am. Chem. Soc. 2003, 125: 14120

<A NAME="RU00811ST-2E">2e</A> Mancini I. Guella G. Zibrowius H. Pietra F. Tetrahedron 2003, 59: 8757

<A NAME="RU00811ST-2F">2f</A> Kam T.-S. Choo Y.-M. J. Nat. Prod. 2004, 67: 547

<A NAME="RU00811ST-3A">3a</A> Somei M. Yamada F. Nat. Prod. Rep. 2005, 22: 73

<A NAME="RU00811ST-3B">3b</A> Reddy R. Jaquith JB. Neelagiri VR. Saleh-Hanna S. Durst T. Org. Lett. 2002, 4: 695

<A NAME="RU00811ST-3C">3c</A> King HD. Meng Z. Denhart D. Mattson R. Kimura R. Wu D. Gao Q. Macor JE. Org. Lett. 2005, 7: 3437

<A NAME="RU00811ST-3D">3d</A> Baran PS. Richter JM. J. Am. Chem. Soc. 2004, 126: 7450

<A NAME="RU00811ST-4A">4a</A> Lv J. Li X. Zhong L. Luo S. Cheng J.-P. Org. Lett. 2010, 12: 1096

<A NAME="RU00811ST-4B">4b</A> Liu Y. Shang D. Zhou X. Zhu Y. Lin L. Liu X. Feng X. Org. Lett. 2010, 12: 180

<A NAME="RU00811ST-4C">4c</A> Singh PK. Singh VK. Org. Lett. 2008, 10: 4121

<A NAME="RU00811ST-4D">4d</A> Yang H. Hong Y.-T. Kim S. Org. Lett. 2007, 9: 2281

<A NAME="RU00811ST-4E">4e</A> Blay G. Fernandez I. Pedro JR. Vila C. Org. Lett. 2007, 9: 2601

<A NAME="RU00811ST-4F">4f</A> Evans DA. Fandrick KR. Song H.-J. J. Am. Chem. Soc. 2005, 127: 8942

<A NAME="RU00811ST-4G">4g</A> Yamazaki S. Iwata Y. J. Org. Chem. 2006, 71: 739

<A NAME="RU00811ST-4H">4h</A> Palomo C. Oiarbide M. Kardak BG. Garcia JM. Linden A. J. Am. Chem. Soc. 2005, 127: 4154

<A NAME="RU00811ST-4I">4i</A> Bandini M. Fagioli M. Melchiorre P. Melloni A. Umani-Ronchi A. Tetrahedron Lett. 2003, 44: 5843

<A NAME="RU00811ST-4J">4j</A> Bandini M. Melloni A. Tommasi S. Umani-Ronchi A. Helv. Chim. Acta 2003, 86: 3753

<A NAME="RU00811ST-5A">5a</A> Evans DA. Scheidt KA. Fandrick KR. Lam HW. Wu J. J. Am. Chem. Soc. 2003, 125: 10780

<A NAME="RU00811ST-5B">5b</A> Evans DA. Fandrick KR. Song H.-J. Scheidt KA. Xu R. J. Am. Chem. Soc. 2007, 129: 10029

<A NAME="RU00811ST-6">6</A> Takenaka N. Abell JP. Yamamoto H. J. Am. Chem. Soc. 2007, 129: 742

<A NAME="RU00811ST-7A">7a</A> Shi Z.-H. Sheng H. Yang K.-F. Jiang J.-X. Lai G.-Q. Lu Y. Xu L.-W. Eur. J. Org. Chem. 2011, 66

<A NAME="RU00811ST-7B">7b</A> Jiang H. Paixoã MW. Monge D. Jørgensen KA.
J. Am. Chem. Soc. 2010, 132: 2775

<A NAME="RU00811ST-7C">7c</A> Bachu P. Akiyama T. Chem. Commun. 2010, 46: 4112

<A NAME="RU00811ST-7D">7d</A> Cai C. Zhao Z.-A. You S.-L. Angew. Chem. Int. Ed. 2009, 48: 7428

<A NAME="RU00811ST-7E">7e</A> Sheng Y.-F. Gu Q. Zhang A.-J. You S.-L. J. Org. Chem. 2009, 74: 6899

<A NAME="RU00811ST-7F">7f</A> Tang H.-Y. Lu A.-D. Zhou Z.-H. Zhao G.-F. He L.-N. Tang C.-C. Eur. J. Org. Chem. 2008, 1406

<A NAME="RU00811ST-7G">7g</A> Bartoli G. Melchiorre P. Synlett 2008, 1759

<A NAME="RU00811ST-7H">7h</A> Rueping M. Nachtsheim BJ. Moreth SA. Bolte M. Angew. Chem. Int. Ed. 2008, 47: 593

<A NAME="RU00811ST-7I">7i</A> Nakamura S. Hyodo K. Nakamura Y. Shibata N. Toru T. Adv. Synth. Catal. 2008, 350: 1443

<A NAME="RU00811ST-7J">7j</A> Li C.-F. Liu H. Liao J. Cao Y.-J. Liu X.-P. Xiao W.-J. Org. Lett. 2007, 9: 1847

<A NAME="RU00811ST-7K">7k</A> Chen W. Du W. Yue L. Li R. Wu Y. Ding L.-S. Chen Y.-C. Org. Biomol. Chem. 2007, 5: 816

<A NAME="RU00811ST-7L">7l</A> Bartoli G. Bosco M. Carlone A. Pesciaioli F. Sambri L. Melchiorre P. Org. Lett. 2007, 9: 1403

<A NAME="RU00811ST-7M">7m</A> Li H. Wang Y.-Q. Deng L. Org. Lett. 2006, 8: 4063

<A NAME="RU00811ST-7N">7n</A> Török B. Abid M. London G. Esquibel J. Török M. Mhadgut SC. Yan P. Prakash GKS. Angew.Chem. Int. Ed. 2005, 44: 3086

<A NAME="RU00811ST-7O">7o</A> Austin JF. MacMillan DWC. J. Am. Chem. Soc. 2002, 124: 1172

For recent selected examples of the enantioselective reactions catalyzed by chiral palladium complexes, see:

<A NAME="RU00811ST-8A">8a</A> Lectard S. Hamashima Y. Sodeoka M. Adv. Synth. Catal. 2010, 352: 2708

<A NAME="RU00811ST-8B">8b</A> Sodeoka M. Hamashima Y. Chem. Commun. 2009, 5787

<A NAME="RU00811ST-8C">8c</A> Hamashima Y. Sasamoto N. Umebayashi N. Sodeoka M. Chem. Asian J. 2008, 3: 1443

<A NAME="RU00811ST-8D">8d</A> Hamashima Y. Sasamoto N. Hotta D. Somei H. Umebayashi N. Sodeoka M. Angew. Chem. Int. Ed. 2005, 44: 1525

<A NAME="RU00811ST-8E">8e</A> Smith AMR. Rzepa HS. White AJP. Billen D. Hii KK. J. Org. Chem. 2010, 75: 3085

<A NAME="RU00811ST-8F">8f</A> Smith AMR. Billen D. Hii KK. Chem. Commun. 2009, 3925

<A NAME="RU00811ST-8G">8g</A> Phua PH. Mathew SP. White AJP. de Vries JG. Blackmond DG. Hii KK. Chem. Eur. J. 2007, 13: 4602

<A NAME="RU00811ST-9A">9a</A> Yoon SJ. Kang YK. Kim DY. Synlett 2011, 420

<A NAME="RU00811ST-9B">9b</A> Moon HW. Kim DY. Bull. Korean Chem. Soc. 2011, 32: 291

<A NAME="RU00811ST-9C">9c</A> Kang YK. Kim SM. Kim DY. J. Am. Chem. Soc. 2010, 132: 11847

<A NAME="RU00811ST-9D">9d</A> Kang SH. Kim DY. Adv. Synth. Catal. 2010, 352: 2783

<A NAME="RU00811ST-9E">9e</A> Lee JH. Kim DY. Synthesis 2010, 1860

<A NAME="RU00811ST-9F">9f</A> Moon HW. Kim DY. Tetrahedron Lett. 2010, 51: 2906

<A NAME="RU00811ST-9G">9g</A> Lee JH. Kim DY. Adv. Synth Catal. 2009, 351: 1779

<A NAME="RU00811ST-9H">9h</A> Kang YK. Kim DY. J. Org. Chem. 2009, 74: 5734

<A NAME="RU00811ST-9I">9i</A> Moon HW. Cho MJ. Kim DY. Tetrahedron Lett. 2009, 50: 4896

<A NAME="RU00811ST-9J">9j</A> Kwon BK. Kim SM. Kim DY. J. Fluorine Chem. 2009, 130: 259

<A NAME="RU00811ST-9K">9k</A> Oh Y. Kim SM. Kim DY. Tetrahedron Lett. 2009, 50: 4674

<A NAME="RU00811ST-9L">9l</A> Kang SH. Kim DY. Bull. Korean Chem. Soc. 2009, 30: 1439

<A NAME="RU00811ST-9M">9m</A> Kwon BK. Kim DY. Bull. Korean Chem. Soc. 2009, 30: 1441

<A NAME="RU00811ST-9N">9n</A> Mang JY. Kwon DG. Kim DY. Bull. Korean Chem. Soc. 2009, 30: 249

<A NAME="RU00811ST-9O">9o</A> Kim SM. Lee JH. Kim DY. Synlett 2008, 2659

<A NAME="RU00811ST-9P">9p</A> Jung SH. Kim DY. Tetrahedron Lett. 2008, 49: 5527

<A NAME="RU00811ST-9Q">9q</A> Park EJ. Kim MH. Kim DY. J. Org. Chem. 2004, 69: 6897

<A NAME="RU00811ST-9R">9r</A> Kim DY. Choi YJ. Park HY. Joung CU. Koh KO. Mang JY. Jung K.-Y. Synth. Commun. 2003, 33: 435

<A NAME="RU00811ST-9S">9s</A> Kim DY. Park EJ. Org. Lett. 2002, 4: 545

<A NAME="RU00811ST-9T">9t</A> Kim DY. Huh SC. Kim SM. Tetrahedron Lett. 2001, 42: 6299

<A NAME="RU00811ST-9U">9u</A> Kim DY. Huh SC. Tetrahedron 2001, 57: 8933

<A NAME="RU00811ST-10A">10a</A> Kang SH. Kang YK. Kim DY. Tetrahedron 2009, 65: 5676

<A NAME="RU00811ST-10B">10b</A> Kim EJ. Kang YK. Kim DY. Bull. Korean Chem. Soc. 2009, 30: 1437

<A NAME="RU00811ST-10C">10c</A> Lee NR. Kim SM. Kim DY. Bull. Korean Chem. Soc. 2009, 30: 829

<A NAME="RU00811ST-10D">10d</A> Kang YK. Kim DY. Bull. Korean Chem. Soc. 2008, 29: 2093

<A NAME="RU00811ST-10E">10e</A> Lee JH. Bang HT. Kim DY. Synlett 2008, 1821

<A NAME="RU00811ST-10F">10f</A> Kang YK. Cho MJ. Kim SM. Kim DY. Synlett 2007, 1135

<A NAME="RU00811ST-10G">10g</A> Cho MJ. Kang YK. Lee NR. Kim DY. Bull. Korean Chem. Soc. 2007, 28: 2191

<A NAME="RU00811ST-10H">10h</A> Kim SM. Kang YK. Cho MJ. Kim DY. Bull. Korean Chem. Soc. 2007, 28: 2435

<A NAME="RU00811ST-10I">10i</A> Cho MJ. Kang YK. Lee NR. Kim DY. Bull. Korean Chem. Soc. 2007, 28: 2191

<A NAME="RU00811ST-10J">10j</A> Kim SM. Kang YK. Lee K. Mang JY. Kim DY. Bull. Korean Chem. Soc. 2006, 27: 423

<A NAME="RU00811ST-10K">10k</A> Kang YK. Kim DY. Tetrahedron Lett. 2006, 47: 4265

<A NAME="RU00811ST-10L">10l</A> Kim HR. Kim DY. Tetrahedron Lett. 2005, 46: 3115

<A NAME="RU00811ST-10M">10m</A> Kim SM. Kim HR. Kim DY. Org. Lett. 2005, 7: 2309

Typical Procedure
To a stirred solution of (E)-diethyl 1-oxobut-2-enylphos-phonate (2a, 20.6 mg, 0.1 mmol), Pd catalyst 1c (5.4 mg, 0.005 mmol) in CH₂Cl₂ (1 mL) was added indole (3a, 14.0 mg, 0.12 mmol) at r.t. The reaction mixture was stirred for 2 h at r.t. Then MeOH (0.15 mL), followed by DBU (0.03 mL), was added directly to the reaction mixture. The reaction was allowed to stir for 2 h at r.t. The reaction was diluted with EtOAc (10 mL), then washed with sat. NH₄Cl. The organic layer was dried over anhyd MgSO₄, filtered, concentrated, and purified by flash column chromatography (EtOAc-hexane, 1:5) to afford (S)-methyl 3-(1H-indol-3-yl)butanoate (4a, 70%, 15.2 mg). [α]_D ^²8 7.3 (c 0.7, CHCl₃, 93% ee). ^¹H NMR (200 MHz, CDCl₃): δ = 7.99 (br s, 1 H), 7.63 (d, J = 7.8 Hz, 1 H), 7.28 (d, J = 7.6 Hz, 1 H), 7.23-7.05 (m, 2 H), 6.90 (d, J = 2.5 Hz, 1 H), 3.65-3.47 (m, 1 H), 3.62 (s, 3 H), 2.82 (dd, J = 14.8, 6.0 Hz, 1 H), 2.56 (dd, J = 14.7, 8.7 Hz, 1 H), 1.39 (d, J = 6.9 Hz, 3 H). ^¹³C NMR (50 MHz, CDCl₃): δ = 173.0, 136.1, 125.9, 121.5, 120.2, 119.7, 118.8, 118.7, 110.9, 51.1, 41.9, 27.6, 20.6. ESI-MS: m/z = 217.9 [M + H]⁺, 117.0, 120.9, 123.0 147.0, 176.9. HPLC (hexane-i-PrOH = 90:10, 220 nm, 0.8 mL/min) Chiralcel OD-H column, t _R = 9.0 min(minor), t _R = 13.8 (major).

The two-site-binding interaction between substrate and palladium catalyst is crucial to guarantee reactivity as well as stereocontrol. In fact, when the monodentate ethyl (E)-but-2-enoate was reacted with indole under the same reaction conditions, no reaction occurred.