Subscribe to RSS
DOI: 10.1055/s-2005-863710
Asymmetric Michael Addition of Arylthiols to α,β-Unsaturated Carbonyl Compounds Catalyzed by Bifunctional Organocatalysts
Publication History
Publication Date:
22 February 2005 (online)
Abstract
Bifunctional chiral organocatalysts comprising thiourea and tertiary amine groups were synthesized. They act as efficient catalysts for asymmetric Michael addition of arylthiols to α,β-unsaturated carbonyl compounds. Enantioselectivity up to 85% has been achieved. Asymmetric α-protonation reaction (up to 60% ee) can be obtained in the presence of the bifunctional catalyst.
Key words
bifunctional organocatalyst - thiourea - hydrogen bonding - asymmetric Michael addition - asymmetric protonation
- For recent reviews on organocatalysis involving hydrogen bonding, see:
-
1a
Pihko PM. Angew. Chem. Int. Ed. 2004, 43: 2062 -
1b
Dalko PI.Moisan L. Angew. Chem. Int. Ed. 2004, 43: 5138 - For recent reviews on organocatalysis by proline and proline derivatives, see:
-
2a
List B. Acc. Chem. Res. 2004, 37: 548 -
2b
Notz W.Tanaka F.Barbas CF. Acc. Chem. Res. 2004, 37: 580 -
2c
List B. Tetrahedron 2002, 58: 5573 -
3a
Huang Y.Rawal VH. J. Am. Chem. Soc. 2002, 124: 9662 -
3b
Huang Y.Unni AK.Thadani AN.Rawal VH. Nature 2003, 424: 146 -
3c
McDougal NT.Schaus SE. J. Am. Chem. Soc. 2003, 125: 12094 -
3d
Thadani AN.Stankovic AR.Rawal VH. Proc. Natl. Acad. Sci., U.S.A. 2004, 101: 5839 -
3e
Uraguchi D.Sorimachi K.Terada M. J. Am. Chem. Soc. 2004, 126: 11804 ; and references therein -
4a
Vachal P.Jacobsen EN. J. Am. Chem. Soc. 2002, 124: 10012 -
4b
Wenzel AG.Jacobsen EN. J. Am. Chem. Soc. 2002, 124: 12964 -
4c
Wenzel AG.Jacobsen EN. Synlett 2003, 1919 -
4d
Joly GD.Jacobsen EN. J. Am. Chem. Soc. 2004, 126: 4102 - For a review, see:
-
5a
Schreiner PR. Chem. Soc. Rev. 2003, 32: 289 -
5b For thiourea as ligand in transition metal-catalyzed reactions, see:
Yang D.Chen Y.-C.Zhu N.-Y. Org. Lett. 2004, 6: 1577 ; and references therein -
6a
Okino T.Hoashi Y.Takemoto Y. J. Am. Chem. Soc. 2003, 125: 12672 -
6b
Okino T.Nakamura S.Furukawa T.Takemoto Y. Org. Lett. 2004, 6: 625 -
6c
Okino T.Hoashi Y.Furukawa T.Xu X.Takemoto Y. J. Am. Chem. Soc. 2005, 127: 119 -
6d Achiral F-C alkylation with nitroolefin, see:
Dessole G.Herrera RP.Ricci A. Synlett 2004, 2374 -
7a
Sohtome Y.Tanatani A.Hashimoto Y.Nagasawa K. Chem. Pharm. Bull. 2004, 52: 477 -
7b
Sohtome Y.Tanatani A.Hashimoto Y.Nagasawa K. Tetrahedron Lett. 2004, 45: 5589 - For a review on enantioselective 1,4-addition of thiol to activated olefin, see:
-
8a
Fehr C. Angew. Chem., Int. Ed. Engl. 1996, 35: 2566 -
8b For recent examples, see:
Nishimura K.Ono M.Nagaoka Y.Tomioka K. J. Am. Chem. Soc. 1997, 119: 12974 -
8c
Emori E.Arai T.Sasai H.Shibashaki M. J. Am. Chem. Soc. 1998, 120: 4043 -
8d
Kanemasa S.Oderaotoshi Y.Wada E. J. Am. Chem. Soc. 1999, 121: 8675 -
8e
Kobayashi S.Ogawa C.Kawamura M.Sugiura M. Synlett 2001, 983 -
8f
McDaid P.Chen Y.Deng L. Angew. Chem. Int. Ed. 2002, 41: 338 -
8g
Nishimura K.Tomioka K. J. Org. Chem. 2002, 67: 431 -
8h
Matsumoto K.Watanabe A.Uchida T.Ogi K.Katsuki T. Tetrahedron Lett. 2004, 45: 2385 -
9a For a recent review on asymmetric catalysis with modified cinchona alkaloids, see:
Tian S.-K.Chen Y.Hang J.Tang L.McDaid P.Deng L. Acc. Chem. Res. 2004, 37: 621 -
9b For late examples, see:
Zhu C.Shen X.Nelson SG. J. Am. Chem. Soc. 2004, 126: 5352 -
9c
Li H.Wang Y.Tang L.Deng L. J. Am. Chem. Soc. 2004, 126: 9906 -
9d
Saaby S.Bella M.Jørgensen KA. J. Am. Chem. Soc. 2004, 126: 8120 -
9e
Acocella MR.Mancheno OG.Bella M.Jørgensen KA. J. Org. Chem. 2004, 69: 8165 - 10
Brunner H.Bügler J.Nuber B. Tetrahedron: Asymmetry 1995, 6: 1699 -
11a
Goodman SN.Jacobsen EN. Adv. Synth. Catal. 2002, 344: 953 -
11b For enantioselective 1,4-addition with unsaturated imide, see:
Sammis GM.Danjo H.Jacobsen EN. J. Am. Chem. Soc. 2004, 126: 9928 ; and references therein -
11c
We failed to get the desired Michael addition product using cinnamoyl-2-oxazolidinone as the receptor.
- 12
Schreiner PR.Wittkopp A. Org. Lett. 2002, 4: 217 - 13
Kaik M.Gawroñski J. Tetrahedron: Asymmetry 2003, 14: 1559 -
16a
Okino T.Hoashi Y.Takemoto Y. Tetrahedron Lett. 2003, 44: 2817 -
16b
Wittkopp A.Shreiner PR. Chem.-Eur. J. 2003, 9: 407 - For catalytic asymmetric protonation in Michael additions of thiols, see:
-
17a
Pracejus VH.Wilcke F.-W.Hanemann K. J. Prakt. Chem. 1977, 319: 219 -
17b
Kumar A.Salunkhe RV.Rane RA.Dike SY. J. Chem. Soc., Chem. Commun. 1991, 485 ; also see ref. 7c -
17c For catalytic protonation of enolate, see:
Ishihara K.Nakashima D.Hiraiwa Y.Yamamoto H. J. Am. Chem. Soc. 2003, 125: 24 ; and references therein -
17d
Hamashima Y.Somei H.Shimura Y.Tamura T.Sodeoka M. Org. Lett. 2004, 6: 1861
References
HRMS data of new organocatalysts: 1a, 564.1770 (calcd 564.1782); 1b, 564.1781 (calcd 564.1782); 1f, 501.1853 (calcd 501.1861); 1g, 701.1728 (calcd 701.1734).
15General Experimental Procedure for ( S , S )-1d-Catalyzed Asymmetric Michael Addition. Phenylthiol (12 µL, 0.11 mmol) was added to the stirred solution of α,β-unsaturated imide 7a (25.1 mg, 0.1 mmol) and 1d (4.2 mg, 0.01 mmol) in 0.5 mL CH2Cl2 at -40 °C. The reaction was stirred for 72 h. Flash chromatography eluting with petroleum ether-EtOAc (10:1) gave the product as a white solid (35.3 mg, 98%). 1H NMR (400 MHz, CDCl3): δ = 9.47 (s, NH), 7.78-7.76 (m, 2 H), 7.62-7.59 (m, 1 H), 7.51-7.47 (m, 2 H), 7.36-7.32 (m, 4 H), 7.29-7.19 (m, 6 H), 4.85 (dd, J = 1.6, 8.4 Hz, 1 H), 3.77 (dd, J = 8.4, 15.6 Hz, 1 H), 3.62 (dd, J = 8.4, 15.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 173.3, 165.6, 140.8, 133.9, 133.3, 133.1, 132.4, 128.9, 128.8, 128.4, 127.8, 127.7, 127.6, 127.4, 48.2, 43.8. ESI-MS: m/z = 360.1 [M - H]-; ee was determined by HPLC on Daicel Chiralcel OD (20% 2-propanol in hexane, 0.5 mL/min, t S = 10.8 min, t R = 12.1 min, 75% ee).
18The absolute configuration was determined by the rotation after conversion to ethyl ester.8c