Short Synthesis of a Biphenyl-Based Amino Triflamide Catalyst and Its Application in Enamine Catalysis

This paper is dedicated to Professor Hisashi Yamamoto on the occasion of his 80^th birthday.

Abstract

A novel axially chiral biphenyl-based amino triflamide has been designed and successfully synthesized from 1-nitropyrene in 6 steps. This chiral amino triflamide functions as effective catalyst for asymmetric Mannich reaction through enamine intermediates.

Key words

axial chirality - biphenyl - amine organocatalyst - enamine catalysis - Mannich reaction - aminoxylation

Publication History

Received: 31 March 2023

Accepted after revision: 10 May 2023

Accepted Manuscript online:
10 May 2023

Article published online:
26 June 2023

• References and Notes


For pioneering works in enamine catalysis, see:
• 1a Eder U, Sauer G, Wiechert R. Angew. Chem. Int. Ed. Engl. 1971; 10: 496
• 1b Hajos ZG, Parrish DR. J. Org. Chem. 1974; 39: 1615
• 1c List B, Lerner RA, Barbas CF. III. J. Am. Chem. Soc. 2000; 122: 2395

For reviews, see:
• 2a Marigo M, Jørgensen KA. Chem. Commun. 2006; 2001
• 2b Mukherjee S, Yang JW, Hoffmann S, List B. Chem. Rev. 2007; 107: 5471
• 2c Melchiorre P, Marigo M, Carlone A, Bartoli G. Angew. Chem. Int. Ed. 2008; 47: 6138
• 2d Melchiorre P. Angew. Chem. Int. Ed. 2012; 51: 9748
• 3a Kano T, Yamaguchi Y, Tokuda O, Maruoka K. J. Am. Chem. Soc. 2005; 127: 16408
• 3b Kano T, Yamaguchi Y, Tanaka Y, Maruoka K. Angew. Chem. Int. Ed. 2007; 46: 1738
• 3c Kano T, Yamaguchi Y, Maruoka K. Angew. Chem. Int. Ed. 2009; 48: 1838
• 3d Kano T, Yamaguchi Y, Maruoka K. Chem. Eur. J. 2009; 15: 6678
• 3e Kano T, Noishiki A, Sakamoto R, Maruoka K. Chem. Commun. 2011; 47: 10626
• 3f Kano T, Sakamoto R, Akakura M, Maruoka K. J. Am. Chem. Soc. 2012; 134: 7516
• 3g Kano T, Sakamoto R, Yamaguchi Y, Itoh K, Maruoka K. Chem. Commun. 2013; 49: 1118
• 3h Kano T, Sakamoto R, Maruoka K. Chem. Commun. 2014; 50: 942
• 3i Kano T, Sakamoto R, Maruoka K. Org. Lett. 2014; 16: 944

A similar biphenyl-based amine catalyst has also been developed, see:
• 4a Kano T, Sugimoto H, Maruoka K. J. Am. Chem. Soc. 2011; 133: 18130
• 4b Kano T, Song S, Kubota Y, Maruoka K. Angew. Chem. Int. Ed. 2012; 51: 1191
• 4c Kano T, Song S, Maruoka K. Chem. Commun. 2012; 48: 7037
• 5a Ohta T, Ito M, Inagaki K, Takaya H. Tetrahedron Lett. 1993; 34: 1615
• 5b Egami H, Sato K, Asada J, Kawato Y, Hamashima Y. Tetrahedron 2015; 71: 6384
• 5c Konishi H, Hoshino F, Manabe K. Chem. Pharm. Bull. 2016; 64: 1438
• 6a Takeshima A, Kano T, Maruoka K. Org. Lett. 2019; 21: 8071
• 6b Homma C, Takeshima A, Kano T, Maruoka K. Chem. Sci. 2021; 12: 1445
• 6c Homma C, Kano T, Maruoka K. Chem. Commun. 2021; 57: 2808
• 6d Homma C, Yamanaka M, Kano T, Maruoka K. Tetrahedron 2021; 91: 132225
• 7 Agranat I, Rabinovitz M, Shaw W.-C. J. Org. Chem. 1979; 44: 1936
• 8 Vachon J, Rentsch S, Martinez A, Marsol C, Lacour J. Org. Biomol. Chem. 2007; 5: 501
• 9 Kobayashi Y, Sano K, Saigo K. Tetrahedron Lett. 2009; 50: 799
• 10 Firth JD, O’Brien P, Ferris L. J. Am. Chem. Soc. 2016; 138: 651
• 11a Franzen J, Marigo M, Fielenbach D, Wabnitz TC, Kjærsgaard A, Jørgensen KA. J. Am. Chem. Soc. 2005; 127: 18296
• 11b Mitsumori S, Zhang H, Cheong PH.-Y, Houk KN, Tanaka F, Barbas CF. III. J. Am. Chem. Soc. 2006; 128: 1040
• 12a Córdova A, Watanabe S, Tanaka F, Notz W, Barbas CF. III. J. Am. Chem. Soc. 2002; 124: 1866
• 12b Hayashi Y, Tsuboi W, Ashimine I, Urushima T, Shoji M, Sakai K. Angew. Chem. Int. Ed. 2003; 42: 3677
• 12c Cobb AJ. A, Shaw DM, Ley SV. Synlett 2004; 558
• 12d Córdova A. Chem. Eur. J. 2004; 10: 1987
• 12e Yang JW, Stadler M, List B. Angew. Chem. Int. Ed. 2007; 46: 609
• 13a Kano T, Yamamoto A, Maruoka K. Tetrahedron Lett. 2008; 49: 5369
• 13b Kano T, Yamamoto A, Shirozu F, Maruoka K. Synthesis 2009; 1557
• 14a Brown SP, Brochu MP, Sinz CJ, MacMillan DW. C. J. Am. Chem. Soc. 2003; 125: 10808
• 14b Zhong G. Angew. Chem. Int. Ed. 2003; 42: 4247
• 14c Hayashi Y, Yamaguchi J, Hibino K, Shoji M. Tetrahedron Lett. 2003; 44: 8293
• 14d Hayashi Y, Yamaguchi J, Sumiya T, Shoji M. Angew. Chem. Int. Ed. 2004; 43: 1112
• 14e Momiyama N, Torii H, Saito S, Yamamoto H. Proc. Natl. Acad. Sci. U.S.A. 2004; 101: 5374
• 15a Novikov R, Bernardinelli G, Lacour J. Adv. Synth. Catal. 2008; 350: 1113
• 15b Harthong S, Brun E, Grass S, Besnard C, Bürgic T, Lacour J. Synthesis 2016; 48: 3254
• 16 Typical Procedure for the Catalytic Asymmetric Mannich Reaction of N-PMP-Protected α-Iminoacetate 9 To a stirred solution of (S)-4 (0.9 mg, 0.0025 mmol) in dioxane (2.5 mL) were added an aldehyde (0.75 mmol) and ethyl (4-methoxyphenylimino)acetate 9 (48.9 μL, 0.25 mmol) in this order at room temperature. After being stirred at the same temperature, the reaction mixture was then quenched with a saturated aqueous NH₄Cl solution and extracted with ethyl acetate. The combined organic extracts were dried over Na₂SO₄, filtered, and concentrated. The residue was purified by flash column chromatography on silica gel (hexane/ethyl acetate = 8:1 to 4:1) to give the corresponding Mannich adduct 10. Ethyl (2S,3R)-3-Formyl-2-(p-methoxyphenylamino)heptanoate (10a) Following the typical procedure, using hexanal (91.6 μL, 0.75 mmol) for 4 h gave the crude product. Purification by flash column chromatography gave the title compound (67 mg, 0.22 mmol, 87% yield, dr = 12:1, 91% ee). ¹H NMR (500 MHz, CDCl₃): δ = 9.65 (d, J = 2.5 Hz, 1 H), 6.80–6.76 (m, 2 H), 6.67–6.63 (m, 2 H), 4.26 (d, J = 6.0 Hz, 1 H), 4.18 (qd, J = 7.1, 3.0 Hz, 2 H), 3.74 (s, 3 H), 2.78–2.71 (m, 1 H), 1.79–1.68 (m, 1 H), 1.67–1.50 (m, 2 H), 1.44–1.28 (m, 3 H), 1.22 (t, J = 7.3 Hz, 3 H), 0.89 (t, J = 7.0 Hz, 3 H). HPLC analysis: Daicel CHIRALPAK IC-3, hexane/i-PrOH (19:1), 1.0 mL/min, λ = 254 nm, t _major = 28.5 min, t _minor = 39.0 min.