435 research outputs found

    Zinc chloride catalyzed addition reactions of propargyl chlorides with acyclic 1,3-dienes

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    Diastereoselective synthesis of ő≤- and ő≥2-muurolene. A carbocationic pathway from mono- to sesquiterpenes

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    The Lewis acid catalysed addition of the piperityl chlorides 6 to isoprene yields adduct 7, which undergoes a cis-stereoselective cyclisation to give the diastereoisomeric muurolene monohydrochlorides 8. Treatment with potassium tert-butoxide affords ő≤- and ő≥2- muurolene 2

    [2+2]-cycloadditions of alkenes with the triphenylallenyl cation

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    The triphenylallenyl cation (8), generated from triphenylpropynol (7) and FSO3H, reacts with alkenes to give the allyl cations 12, which may be deprotonated to yield the methyleneccylobutenes 14. Alternatively, 12 can be converted into the 2-vinyl-indenes 13 two subsequent electrocyclic reactions

    Addition and cycloaddition reactions of allenyl cations with various cycloalka-1,3-dienes

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    Allenyl cations , generated from propargyl chlorides and zinc chloride give monocyclic adducts or [3+4] and [2+4] cycloaddition products with various cycloalka-1,3-dienes. The mode of addition depends on R and the ring size of the 1,3-dienes
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