Phosphorodiamidic Acid as a Novel Structural Motif of Brønsted Acid Catalysts for Direct Mannich Reaction of N-Acyl Imines with 1,3-Dicarbonyl Compounds

Abstract

Phosphorodiamidic acid 1 was developed as an efficient Brønsted acid catalyst for the direct Mannich reaction of N-acyl imines with 1,3-dicarbonyl compounds. Phosphorodiamidic acids were proposed as a novel structural motif of enantioselective ­Brønsted acid catalysts because they possess unique features, including the capability of introducing various substituents to the nitrogen atoms and the preparation from readily available chiral diamines in a short step. We demonstrated that chiral phosphorodiamidic acid 1b derived from binaphthalene bis(sulfonamide) functioned as an enantioselective catalyst to give the Mannich product in an optically active form.

Key words

organocatalyst - Mannich reaction - green chemistry - asymmetric catalysis - imines

References and Notes

• Reviews on atom economy:
• 2a Trost BM. Science  1991,  254:  1471 
• 2b Trost BM. Angew. Chem., Int. Ed. Engl.  1995,  34:  259 
• 2c Trost BM. Acc. Chem. Res.  2002,  35:  695 
• Recent reviews on organocatalysis:
• 3a Dalko PL. Moisan L. Angew. Chem. Int. Ed.  2004,  43:  5138 
• 3b

  Special issue on ‘Organic Catalysis’: Adv. Synth. Catal. 2004, 346.

• 3c

  Special issue on ‘Enantioselective Organocatalysis’: Acc. Chem. Res. 2004, 37.

• 3d Berkessel A. Gröger H. Asymmetric Organocatalysis - From Biomimetic Concepts to Powerful Methods for Asymmetric Synthesis   Wiley-VCH; Weinheim: 2005. 
• 3e Seayad J. List B. Org. Biomol. Chem.  2005,  3:  719 
• 3f Hayashi Y. J. Synth. Org. Chem. Jpn.  2005,  63:  464 
• For reviews on Brønsted acid catalysis, see:
• 4a Schreiner PR. Chem. Soc. Rev.  2003,  32:  289 
• 4b Pihko PM. Angew. Chem. Int. Ed.  2004,  43:  2062 
• For selected recent examples of asymmetric Brønsted acid catalysis, see:
• 5a Huang Y. Unni AK. Thadani AN. Rawal VH. Nature (London)  2003,  424:  146 
• 5b Joly GD. Jacobsen EN. J. Am. Chem. Soc.  2004,  126:  4102 
• 5c Thadani AN. Stankovic AR. Rawal VH. Proc. Natl. Acad. Sci. U.S.A.  2004,  101:  5846 
• 5d Du H. Zhao D. Ding K. Chem.-Eur. J.  2004,  10:  5964 
• 5e Momiyama N. Yamamoto H. J. Am. Chem. Soc.  2005,  127:  1080 
• 5f Unni AK. Takenaka N. Yamamoto H. Rawal VH. J. Am. Chem. Soc.  2005,  127:  1336 
• 5g Fuerst DE. Jacobsen EN. J. Am. Chem. Soc.  2005,  127:  8964 
• 5h Rueping M. Sugiono E. Azap C. Theissmann T. Bolte M. Org. Lett.  2005,  7:  3781 
• 5i Zhuang W. Hazell RG. Jørgensen KA. Org. Biomol. Chem.  2005,  3:  2566 
• 5j Zhuang W. Poulsen TB. Jørgensen KA. Org. Biomol. Chem.  2005,  3:  3284 
• 5k Tonoi T. Mikami K. Tetrahedron Lett.  2005,  46:  6355 
• 5l Herrera RP. Sgarzani V. Bernardi L. Ricci A. Angew. Chem. Int. Ed.  2005,  44:  6576 
• 6a Lewis Acid Reagents: A Practical Approach   Yamamoto H. Oxford University Press; Oxford: 1999. 
• 6b Lewis Acids in Organic Synthesis   Yamamoto H. Wiley-VCH; Weinheim: 2000. 
• 7a Akiyama T. Itoh J. Yokota K. Fuchibe K. Angew. Chem. Int. Ed.  2004,  43:  1566 
• 7b Akiyama T. Morita H. Itoh J. Fuchibe K. Org. Lett.  2005,  7:  2583 
• 8a Uraguchi D. Terada M. J. Am. Chem. Soc.  2004,  126:  5356 
• 8b Uraguchi D. Sorimachi K. Terada M. J. Am. Chem. Soc.  2004,  126:  11804 
• 8c Uraguchi D. Sorimachi K. Terada M. J. Am. Chem. Soc.  2005,  127:  9630 
• For stereoselective direct Mannich reaction catalyzed by achiral Brønsted acid, see:
• 9a Wu Y.-S. Cai J. Hu Z.-Y. Lin G.-X. Tetrahedron Lett.  2004,  45:  8949 
• 9b Akiyama T. Matsuda K. Fuchibe K. Synlett  2005,  322 
• 10a Review: Lucet D. Le Gall T. Mioskowski C. Angew. Chem. Int. Ed.  1998,  37:  2581 ; and references therein
• 10b Corey EJ. Imwinkelried R. Pikul S. Xiang YB. J. Am. Chem. Soc.  1989,  111:  5493 
• 10c Corey EJ. Yu C.-M. Kim SS. J. Am. Chem. Soc.  1989,  111:  5495 
• 12a For an excellent review of organocatalytic asymmetric direct Mannich reactions, see: Córdova A. Acc. Chem. Res.  2004,  37:  102 
• See also:
• 12b Poulsen TB. Alemparte C. Saaby S. Bella M. Jørgensen KA. Angew. Chem. Int. Ed.  2005,  44:  2896 
• 12c

  See ref. 3d, Chapter 5.2.

• For metal complex-mediated asymmetric direct Mannich reactions, see:
• 13a Juhl K. Gathergood N. Jørgensen KA. Angew. Chem. Int. Ed.  2001,  40:  2995 
• 13b Trost BM. Terrell LR. J. Am. Chem. Soc.  2003,  125:  338 
• 13c Matsunaga S. Kumagai N. Harada S. Shibasaki M. J. Am. Chem. Soc.  2003,  125:  4712 
• 13d Bernardi L. Gothelf AS. Hazell RG. Jørgensen KA. J. Org. Chem.  2003,  68:  2583 
• 13e Marigo M. Kjærsgaard A. Juhl K. Gathergood N. Jørgensen KA. Chem.-Eur. J.  2003,  9:  2359 
• 13f Matsunaga S. Yoshida T. Morimoto H. Kumagai N. Shibasaki M. J. Am. Chem. Soc.  2004,  126:  8777 
• 13g Hamashima Y. Sasamoto N. Hotta D. Somei H. Umebayashi N. Sodeoka M. Angew. Chem. Int. Ed.  2005,  44:  1525 
• 13h Yoshida T. Morimoto H. Kumagai N. Matsunaga S. Shibasaki M. Angew. Chem. Int. Ed.  2005,  44:  3470 
• 13i Kjærsgaard A. Jørgensen KA. Org. Biomol. Chem.  2005,  3:  804 
• 13j Kundsen KR. Jørgensen KA. Org. Biomol. Chem.  2005,  3:  1362 
• 14 Greene TW. Wuts PGM. Protective Groups in Organic Synthesis   3rd ed.:  John Wiley and Sons, Inc.; New York: 1999.  p.494-653  
• 15 Nakamura Y. Matsubara R. Kobayashi S. Org. Lett.  2003,  5:  2481 
• For binaphthalene bis(sulfonamide) derivatives as a chiral ligand for metal-based catalysts, see:
• 18a Terada M. Motoyama Y. Mikami K. Tetrahedron Lett.  1994,  35:  6693 
• 18b Mikami K. Motoyama Y. Terada M. Inorg. Chim. Acta  1994,  222:  71 
• 18c Denmark SE. Christenson BL. O’Connor SP. Tetrahedron Lett.  1995,  36:  2219 
• 18d Shi M. Sui W.-S. Chirality  2000,  12:  574 
• 18e Ooi T. Saito A. Maruoka K. J. Am. Chem. Soc.  2003,  125:  3220 
• 18f Yus M. Ramon DJ. Prieto O. Tetrahedron: Asymmetry  2003,  14:  1103 
• 18g Ooi T. Ohmatsu K. Uraguchi D. Maruoka K. Tetrahedron Lett.  2004,  45:  4481 
• 18h Akiyama K. Mikami K. Tetrahedron Lett.  2004,  45:  7217 
• For binaphthalene-derived diazaphosphepines as a chiral ligand for metal-based catalysts, see:
• 19a Reetz MT. Oka H. Goddard R. Synthesis  2003,  1809 
• 19b Denmark SE. Fan Y. J. Am. Chem. Soc.  2003,  125:  7825 
• 19c Monti C. Gennari C. Steele RM. Piarulli U. Eur. J. Org. Chem.  2004,  3557 
• 19d Denmark SE. Beutner GL. Wynn T. Eastgate MD. J. Am. Chem. Soc.  2005,  127:  3774 
• 23 Dubey PK. Kulkarni SM. Kumar RV. Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem.  2002,  41:  1305 

1

Present address: Sagami Chemical Research Center, Ayase 252-1193, Japan.

11

Preparation of Phosphorodiamidic Acid ( 1a).
N,N′-Ditosylbenzene-1,2-diamine (208.3 mg, 0.5 mmol), prepared according to the literature procedure, [23] was dissolved into pyridine (1 mL) under nitrogen atmosphere. To the resulting solution was added phosphorus oxychloride (115.0 mg, 0.75 mmol) at r.t. After being stirred for 12 h at ambient temperature, H₂O (1 mL) was poured into the reaction mixture. The resulting suspension was stirred for additional 30 min. Then, EtOAc was added and all pyridine was removed by reverse extraction with 1 N HCl. The organic phase was dried over Na₂SO₄. After being concentrated, the residue was purified by column chromatography. Compound 1a was isolated as a white solid in 90% yield. ¹H NMR (270 MHz, DMSO-d ₆,): δ = 2.30 (6 H, s), 6.79-6.86 (2 H, m), 7.17-7.24 (2 H, m), 7.31 (4 H, d, J = 8.4 Hz), 8.02 (4 H, d, J = 8.4 Hz). ¹³C NMR (67.8 MHz, DMSO-d ₆): δ = 21.0, 113.1 (d, J _P-C = 5.4 Hz), 122.9, 126.8 (t, J _P-C = 10.3 Hz), 127.9, 129.5, 135.7, 144.2. IR (KBr): 3425, 3072, 1375, 1175, 1119 cm^-1. HRMS (ESI): m/z calcd for C₂₀H₁₉N₂O₆PS₂ [M - H]^-: 477.0349. Found: 477.0351.

16

The distribution of keto-enol tautomers of 3 in CDCl₃ was measured by ¹H NMR. The percentages of the enol form are listed as follows: 3a: 72%; 3b: 61%; 3c: >98%; 3d: 6%; 3e: 6%; 3f: 21%; 3g: <2%.

17

Although in the case of unsymmetrical 1,3-dicarbonyl compounds, keto esters 3d,e and keto amide 3f, the diastereomeric mixtures were obtained, their ratios were changed during the course of experiment.

20

Compound (R)-1b: [α]_D 150 (c 0.99, CHCl₃). ¹H NMR (270 MHz, DMSO-d ₆): δ = 3.33 (6 H, s), 6.23 (4 H, d, J = 8.1 Hz), 6.74 (2 H, d, J = 7.6 Hz), 7.01 (4 H, d, J = 8.1 Hz), 7.10 (2 H, t, J = 7.6 Hz), 7.37 (2 H, t, J = 7.6 Hz), 7.43 (2 H, d, J = 7.6 Hz), 7.73 (2 H, d, J = 7.6 Hz), 7.75 (2 H, d, J = 7.6 Hz). ¹³C NMR (67.8 MHz, DMSO-d ₆): δ = 20.9, 125.3, 125.4, 125.8, 127.1, 127.4 (d, J _P-C = 1.0 Hz), 127.8, 128.1 (t, J _P-C = 1.5 Hz), 130.8 (t, J _P-C = 1.5 Hz), 131.1 (d, J _P-C = 1.0 Hz), 131.5 (d, J _P-C = 1.0 Hz), 132.1, 134.5-134.6 (m), 137.6-137.8 (m), 140.6 (d, J _P-C = 4.9 Hz). IR (KBr): 3458, 3055, 2910, 1344, 1171, 1113 cm^-1. HRMS (ESI): m/z calcd for C₃₄H₂₇N₂O₆PS₂ [M - H]^-: 653.0975. Found 653.0975.

21

Compound 4e: white solid; R _f = 0.20 (hexane-EtOAc, 2:1). HPLC analysis Chiralpak AD-H (hexane-EtOH, 80:20, 1.0 mL/min, 254 nm, 10 °C) 19.1 (S), 27.3 (R) min. ¹H NMR (270 MHz, CDCl₃): δ = 2.12 (3 H, s), 2.32 (3 H, s), 4.41 (1 H, d, J = 4.9 Hz), 6.06 (1 H, dd, J = 9.2, 4.9 Hz), 7.22-7.54 (8 H, m), 7.77-7.86 (2 H, m), 7.97 (1 H, br d, J = 9.2 Hz). ¹³C NMR (67.8 MHz, CDCl₃): δ = 29.8, 31.6, 52.3, 70.0, 126.3, 127.1, 127.8, 128.6, 128.8, 131.8, 133.7, 139.2, 166.8, 202.6, 205.9. IR (KBr): 3369, 3032, 2918, 1724, 1639, 1522 cm^-1. HRMS (ESI): m/z calcd for C₁₉H₁₉NaNO₃ [M + Na]⁺: 332.1257. Found: 332.1260.

22

The absolute configuration of Bz-product 4e was determined after transformation into the stereochemically known N-benzoylphenylglycine methyl ester. The stereochemical determination of 4a and the experimental procedure for derivatization of 4 to N-protected glycine methyl ester were described in ref. 8a.