The PtCl₂-mediated cycloisomerization of unsaturated propargylic carboxylates yields differently functionalized bicyclo[n.1.0]enol esters from moderate to good yields, in a very diastereo-selective manner. In this review, we describe the scope and limitations of this transformation. We have prepared and submitted to PtCl₂-catalyzed cycloisomerization a series of differently substituted hept-1-en-6-ynes with different O-acyl (acetyl, trichloroacetyl, 3,4,5-trimethoxybenzoyl, etc.) protecting groups at propargylic positions, investigating also the effect of the geometry at the double bond, as well as the effect of the number of substituents at the alkene and at terminal position in the alkyne moiety. As a result, we have found that the O-acetyl migrating group is the best one in terms of simplicity and chemical yields. In this reaction we have isolated mixtures of compounds formed by minor 1-acetoxy-allenes and major bicyclo[4.1.0]heptane derivatives. Major products are the result of a sequential process involving steps of cycloisomerization plus cyclopropanation, followed by acyl migration. The basic hydrolysis (K₂CO₃, MeOH) of these intermediates gave mixtures of cis and trans-caran-2-ones. This two-step protocol (cycloisomerizsation plus basic hydrolysis) for the syntheses of a, b-unsaturated cyclopropyl,ketones constitutes a synthetic alternative to the usual unfriendly, intramolecular  cyclopropanation of unsaturated a-diazocarbonyl derivatives. The formation of these bicycle [4.1.0] heptane derivatives is a simple but efficient entry into the skeleton of the carane family of natural products.