PtCl
2 constitutes an efficient and practical catalyst for a set of different atom economical rearrangementreactions of enynes. This includes (i) a formal enyne metathesis reaction delivering 1,3-dienes, (ii) the formationof polycyclic vinylcyclopropane derivatives, and (iii) an unprecedented O
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C allyl shift reaction if unsaturatedethers are employed. Although these transformations produce significantly different structural motifs, theyshare a common mechanism comprising a cationic manifold triggered by the
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-complexation of Pt(II) ontothe alkyne unit of the substrates. Strong experimental support for the proposed mechanism comes fromdeuterium-labeling studies, a careful analysis of the product distribution pattern, and the fact that in somecases PtCl
2 can be replaced by simple Lewis or Br
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nsted acids as the catalysts.