Functionalized allyl halides, useful starting materials for the prepn. of substituted organometallic reagents can be simply obtained by a straightforward approach. Hoveyda's ruthenium carbene catalyst, used in catalytic amt. (2 mol%), is able to promote the cross metathesis of allyl bromide and chloride with a variety of different substituted olefins giving the corresponding functionalized 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 prepn. of valuable precursors for functionalized organometallic reagents. In particular, the use of functionalized allyl bromides in the enantioselective Nozaki-Hiyama reaction promoted by [Cr(Salen)Cl] is presented.
A Cross Metathesis Based Protocol for the Effective Synthesis of Functionalised Allyl Bromides and Chlorides
BANDINI, MARCO;COZZI, PIER GIORGIO;MELCHIORRE, PAOLO;LICCIULLI, SEBASTIANO;UMANI RONCHI, ACHILLE
2004
Abstract
Functionalized allyl halides, useful starting materials for the prepn. of substituted organometallic reagents can be simply obtained by a straightforward approach. Hoveyda's ruthenium carbene catalyst, used in catalytic amt. (2 mol%), is able to promote the cross metathesis of allyl bromide and chloride with a variety of different substituted olefins giving the corresponding functionalized 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 prepn. of valuable precursors for functionalized organometallic reagents. In particular, the use of functionalized allyl bromides in the enantioselective Nozaki-Hiyama reaction promoted by [Cr(Salen)Cl] is presented.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
