Functionalised allyl halides, useful starting materials for the preparation of substituted
organometallic reagents can be simply obtained by a straightforward approach. Hoveyda’s
ruthenium carbene catalyst 3, used in catalytic amount (2 mol%), is able to promote the cross metathesis of allyl bromide and chloride
with a variety of different substituted olefins giving the corresponding functionalised
allyl halides in satisfactory yields. trans-Olefins are obtained as major diastereoisomers reaching 90:10 (trans:cis) ratio when allyl chloride is used as the metathesis partner. This reaction represents
a simple and accessible way for the preparation of valuable precursors for functionalised
organometallic reagents. In particular, the use of functionalised allyl bromides (10b and 13) in the enantioselective Nozaki-Hiyama reaction promoted by [Cr(Salen)Cl] is presented.
allyl halides - cross metathesis - ruthenium catalyst - functionalised olefins