Sc(OTf)₃: A Highly Efficient and Renewable Catalyst for Michael Addition of Indoles to Nitroolefins in Water

REFERENCES

• (a) Li , C. J. ; Chen , L. Organic chemistry in water . Chem. Soc. Rev. 2006 , 35 , 68 – 82 ; (b) Chen , L. ; Li , C. J. Catalyzed reactions of alkynes in water . Adv. Synth. Catal. 2006 , 348 , 1459 – 1484 ; (c) Li , C. J. Organic reactions in aqueous media with a focus on carbon–carbon bond formations: A decade update . Chem. Rev. 2005 , 105 , 3095 – 3165 .
   PubMed Web of Science ®Google Scholar
• (a) Kobayashi , S. ; Manabe , K. Development of novel Lewis acid catalysts for selective organic reactions in aqueous media . Acc. Chem. Res. 2002 , 35 , 209 – 217 ; (b) Lindström , U. M. Stereoselective organic reactions in water . Chem. Rev. 2002 , 102 , 2751 – 2771 ; (c) Kobayashi , Y. ; Mori , Y. ; Nogayama , S. ; Manabe , K. Catalytic asymmetric aldol reactions in water . Green Chem. 1999 , 1 , 175 – 177 .
   PubMed Web of Science ®Google Scholar
• (a) Somei , M. ; Yamada , F. Simple indole alkaloids and those with a non-rearranged monoterpenoid unit . Nat. Prod. Rep. 2005 , 22 , 73 – 103 ; (b) Sundberg, R. J. The Chemistry of Indoles; Academic Press: New York, 1996; p. 113 .
   PubMed Web of Science ®Google Scholar
• (a) Gribble , G. W. Recent developments in indole ring synthesis—Methodology and applications . J. Chem. Soc. Perkin Trans. 1 2000 , 1045 – 1075 ; (b) Moore , R. E. ; Cheuk , C. ; Patterson , G. M. L. Hapalindoles: New alkaloids from the blue-green alga Hapalosiphon fontinalis . J. Am. Chem. Soc. 1984 , 106 , 6456 – 6457 ; (c) Szmuszkovicz , J. Reaction of substituted indoles with methyl vinyl ketone: New synthesis of 2-methylcarbazole . J. Am. Chem. Soc. 1957 , 79 , 2819 – 2821 .
   Google Scholar
• (a) Jia , Y. X. ; Zhu , S. F. ; Yang , Y. ; Zhou , Q. L. Asymmetric Friedel–Crafts alkylations of indoles with nitroalkenes catalysted by Zn(II)–bisoxazoline complexes . J. Org. Chem. 2006 , 71 , 75 – 80 ; (b) Lin , C. ; Hsu , J. ; Sastry , M. N. V. ; Fang , H. ; Tu , Z. ; Liu , J. T. ; Yao , C. F. I2-catalyzed Michael addition of indole and pyrrole to nitroolefins . Tetrahedron 2005 , 61 , 11751 – 11757 ; (c) Komoto , I. ; Kobayashi , S. Lewis acid catalysis in supercritical carbon dioxide: Use of poly(ethylene glycol) derivatives and perfluoroalkylbenzenes as surfactant molecules which enable efficient catalysis in ScCO2 . J. Org. Chem. 2004 , 69 , 680 – 688 ; (d) Wang , S. Y. ; Ji , S. J. ; Loh , T. P. The Michael addition of indole to α,β-unsaturated ketones catalyzed by iodine at room temperature . Synlett 2003 , 2377 – 2379 ; (e) Bandini , M. ; Melchiorre , P. ; Melloni , A. ; Umani-Ronchi , A. A practical indium tribromide–catalyzed addition of indoles to nitroalkenes in aqueous media . Synthesis 2002 , 1110 – 1114 .
   PubMedGoogle Scholar
• Firouzabadi , H. ; Iranpoor , N. ; Nowrouzi , F. The facile and efficient Michael addition of indoles and pyrroles to α,β-unsaturated electron-deficient compounds catalyzed by aluminum dodecyl sulfate trihyrate [Al(DS)3]·3H2O in water . Chem. Commun. 2005 , 789 – 791 .
   PubMedGoogle Scholar
• Azizi , N. ; Arynasab , F. ; Saidi , M. R. Efficient Friedel–Crafts alkylation of indoles and pyrrole with enones and nitroalkene in water. Org. Biomol. Chem. 2006, 4, 4275–4277.
   PubMed Web of Science ®Google Scholar
• Wu , P. ; Wan , Y. ; Cai , J. Carbohydrate-based tolylsulfonyl hydrazines: Effective catalysts for Michael addition of indoles to electron-deficient olefins in water . Synlett 2008 , 1193 – 1198 .
   Google Scholar
• Kumar , V. P. ; Sridhar , R. ; Srinivas , B. ; Narender , M. ; Rao , K. R. Friedel–Crafts alkylation of indoles with nitroolefins in the presence of β-cyclodextrin in water under neutral conditions . Can. J. Chem. 2008 , 86 , 907 – 911 .
   Google Scholar
• Habib , P. M. ; Kavala , V. ; Kuo , C.-W. ; Yao , C. F. Catalyst-free aqueous-mediated conjugative addition of indoles to β-nitrostyrenes . Tetrahedron Lett. 2008 , 49 , 7005 – 7007 .
   Web of Science ®Google Scholar
• (a) Kobayashi , S. ; Sugiura , M. ; Kitagawa , H. ; Lam , W. W.-L. Rare-earth metal triflates in organic synthesis . Chem. Rev. 2002 , 102 , 2227 – 2302 ; (b) Kobayashi , S. Scandium triflate in organic synthesis . Eur. J. Org. Chem. 1999 , 15 – 27 ; (c) Kobayashi , S. ; Busujima , T. ; Nagayama , S. Sc(OTf)3-catalyzed three-component reactions of aldehydes, amines, and allyltributylstannane in micellar system: Facile synthesis of homoallylic amines in water . Chem. Commun. 1998 , 19 – 20 .
   PubMed Web of Science ®Google Scholar
• Mannabe , K. ; Aoyama , N. ; Kobayashi , S. Friedel–Crafts-type conjugate addition of indoles using a Lewis acid–surfactant combined catalyst in water . Adv. Synth. Catal. 2001 , 343 , 174 – 176 .
   Google Scholar
• Kawatsura , M. ; Aburatani , S. ; Uenishi , J. Hafnium trifluoromethanesulfonate [Hf(OTf)4]–catalyzed conjugate addition of indoles to α,β-enones . Synlett 2005 , 2492 – 2494 .
   Google Scholar
• An , L. T. ; Zou , J. P. ; Zhang , L. L. ; Zhang , Y. Sulfamic acid–catalyzed Michael addition of indoles and pyrrole to electron-deficient nitroolefins under solvent-free condition . Tetrahedron Lett. 2007 , 48 , 4297 – 4300 .
   Web of Science ®Google Scholar
• Merchant , J. R. ; Chhatriwalla , K. M. ; Salgar , S. S. ; Patell , J. R. Heterocyclic compounds, XII: Color tests, spectra, and reactions of some indole derivatives . J. Indian Chem. Soc. 1971 , 48 , 613 – 619 .
   Google Scholar
• Kusurkar , R. S. ; Alkobati , N. A. H. ; Gokule , A. S. ; Chaudhari , P. M. ; Waghchaure , P. B. Thermal and microwave-assisted conjugate addition of indole to electron-deficient nitroolefins . Synth. Commun. 2006 , 36 , 1075 – 1081 .
   Web of Science ®Google Scholar