"Phosphate Extension," an intramolecular cyclization reaction developed by P. A. Bartlett, is the phosphorus version of the iodolactonization reaction and results in the formation of chiral 1, 3-diol precursors. Bartlett showed that achiral phosphotriesters affords racemic cyclized products with high diastereoselectivity. To our knowledge, however, enantioselective versions of this reaction have not been examined. The goal of this thesis is to synthesize each of the enantiomeric cyclized products via Phosphate Extension. A library of racemic phosphotriesters chiral at phosphorus with varying alkyl groups were prepared and the methyl and ethyl groups were determined to be the optimal substituents in the phosphate extension reaction. A pair of optically active versions of 3-butenyl ethyl methyl phosphates were then prepared through multi-step pathways involving the employment of chiral auxiliaries and the synthesis of diastereomeric phosphoramidates. These optically pure 3-butenyl ethyl methyl phosphates were then used to generate the enantioenriched Phosphate Extension products.