Indium(III) Bromide-Catalyzed Chemioselective Dimerization of Vinylarenes

Abstract

Indium(III) bromide catalyzes the dimerization of α-substituted vinylarenes. Chemioselectivity towards open chain or cyclic dimers depends on the nature of the substituent at the aryl group of the vinylarene.

Key words

indium(III) bromide - vinylarenes - dimerization - catalysis - chemioselectivity - indans

References

• 1 Bergmann E. Taubadel H. Weib H. Chem. Ber.  1931,  64B:  1493 
• 2a

  For H₃PO₄ see ref. [1]

• 2b For H₂SO₄, HCl and p-toluene sulfonic acid: Petropoulos JC. Fisher JJ. J. Am. Chem. Soc.  1958,  80:  1938 
• 2c for C₂H₅AlCl₂: Wolovsky R. Maoz N. J. Org. Chem.  1973,  38:  4040 
• 3 Ciminale F. Lopez L. Paradiso V. Nacci A. Tetrahedron  1996,  52:  13971 
• 4 Tsuchimoto T. Kamiyama S. Negoro R. Shirakawa E. Kawakami Y. Chem. Commun.  2003,  852 

5

The vinylarenes were prepared from the corresponding methyl aryl ketone upon reaction with an equimolar amount of CH₃MgI in anhyd Et₂O to generate the corresponding 1-aryl-1-methyl-ethanol, which was dehydrated with p-toluenesulfonic acid in anhyd benzene.