Haloaromatic Substituted Olefins by the MC Murry Olefin Synthesis

Abstract

The McMurry olefin synthesis has proved to be one of the methods of choice for the synthesis of symmetrically substituted olefins (eq. 1).¹ This method has also proved useful in the

synthesis of unsymmetrically substituted olefins as well. ^la,lm,2 The attractiveness of the McMurry synthesis rests in the use of a one-pot reaction from usually readily available ketone reactants. Yet with these desirable features, the bulk of the olefins syn-thesized by this method are hydrocarbons.³ Since strong reducing agents (e.g., LiAlH₄, potassium, lithium) are used to produce Ti(0) from TiC1₃, there is a concern as to the use of this method to prepare olefins containing easily reduceable groups.⁴ We have found that it is possible to prepare olefins containing haloaromatic substituents by this method with a slight modification. In fact, it was possible to prepare an olefin containing a m-trifluoromethylphenyl substituent. This opens the McMurry synthesis to a wider range of substituents than previously reported.