Exposure of 1-substituted cyclopropanols to excess Et2Zn promotes its dimerization to afford 2-methylcyclopentane-1,3-diol derivatives as meso compounds in a diastereoselective fashion. The reaction likely proceeds via aldol reaction between two molecules of zinc homoenolate and subsequent intramolecular alkylzinc addition to the carbonyl group. Dehydration of the present product allows for facile preparation of 1,2,3-trisubstituted cyclopentadiene and its transition metal complex.