A highly regioselective cyclopropanation of alpha-allenic alcohols using samarium/dihalomethane provides a variety of methylene- and alkylidenecyclopropane carbinols in good yield. The nearby hydroxyl moiety and the samarium reagent are essential for this unique conversion. A comparison with the more traditional Simmons-Smith conditions and its variants is made. The diastereoselectivity varies from 1:1 to 50:1 and depends on the substituents on the carbinol side chain (R group) and on the substitution of the allene. Unequivocal assignment of the relative stereochemistry of the prepared methylenecyclopropanes has been made on the basis of NMR studies, independent synthesis, and X-ray crystallography. A facile one-pot, two-step enantioselective reduction of ynones with the chiral LiAlH4/Darvon alcohol complex provides the starting allenic alcohols in 82-93% enantiomeric excess. Hydroboration of the methylene-cyclopropane carbinols results in the formation of (Z)-substituted cyclopropyl dicarbinols, which were cyclized to 3-oxabicyclo[3.1.0]hexanes upon treatment with p-TsCl.