Indium(I)-Mediated, Tandem Carbonyl Addition-Oxy-Cope Rearrangement of γ-Pentadienyl Anions to Cyclohexenones and Conjugated Aromatic Ketones

 

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Abstract

Treatment of 5-bromopenta-1,3-diene with indium metal in the presence of α,β-unsaturated ketones results in initial γ-pentadienylation to generate the hydroxy-1,4-diene. In the case of aromatic conjugated ketones or cyclohexenones the indium alkoxide undergoes spontaneous oxy-Cope rearrangement to afford the 1,4-addition product. The second double bond is required for this [3,3] sigmatropic rearrangement as allyl groups fail to under go this in situ rearrangement. This behavior is consistent with an indium(I) pentadiene species and appears to be the first example of an indium-mediated oxy-Cope rearrangement.

Reference

• 1a Woo S. Squires N. Fallis AG. Org. Lett.  1999,  1:  573 
  CrossrefGoogle Scholar
• 1b Hirashita T. Inoue S. Yamamura H. Kawai M. Araki S. J. Organomet. Chem.  1997,  549:  305 
  CrossrefGoogle Scholar
• 2 Negishi E.-I. Organometallics in Organic Synthesis   Vol. 1:  Wiley; New York: 1980.  p.30-59  
  Google Scholar
• 3 Woo S. Legoupy S. Parra S. Fallis AG. Org. Lett.  1999,  1:  1013 
  CrossrefGoogle Scholar
• 4 Kwon O. Park SB. Schreiber SL. J. Am. Chem. Soc.  2002,  124:  13402 
  CrossrefPubMedGoogle Scholar
• 5 Melekhov A. Fallis AG. Tetrahedron Lett.  1999,  40:  7867 
  CrossrefGoogle Scholar
• 6a Gerard F. Miginiac P. Bull. Soc. Chim. Fr.  1974,  1924 
  CrossrefGoogle Scholar
• 6b Wilson SR. Mao DT. Jernberg KM. Ezmirly ST. Tetrahedron Lett.  1977,  2559 
  CrossrefGoogle Scholar
• 7 Evans DA. Nelson JV. J. Am. Chem. Soc.  1980,  102:  774 
  CrossrefGoogle Scholar
• 8 Hrovat DA. Beno BR. Lange H. Yoo H.-Y. Houk KN. Borden WT. J. Am. Chem. Soc.  1999,  121:  10529 
  CrossrefGoogle Scholar
• 9 Doering WE. Wang Y. J. Am. Chem. Soc.  1999,  121:  10112 
  CrossrefGoogle Scholar
• 11 Chan TH. Yang Y. J. Am. Chem. Soc.  1999,  121:  3228 
  CrossrefGoogle Scholar
• 12 Forgione P. Wilson PD. Yap GPA. Fallis AG. Synthesis  2000,  921 
  Article in Thieme ConnectGoogle Scholar
• 13 Haeffner F. Houk KN. Reddy R. Paquette LA. J. Am. Chem. Soc.  1999,  121:  11880 
  CrossrefGoogle Scholar

General Procedure: 5-Bromopenta-1,3-diene (7.21 mmol) and the ketone (1.81 mmol) were dissolved in DMF (1.3 mL) at 0 °C. Indium(powder) was added and the reaction was stirred at 21 °C for 4 h. The reaction was diluted with CH₂Cl₂ (5 mL) and Et₂O (15 mL) and filtered through a silica pad and purified by flash chromatography.