An asymmetric synthesis of a 3'-deoxy-3'-¹⁸F-fluorothymidine (¹⁸F-FLT) precursor has been developed wherein the deoxysugar moiety was synthesized using a novel Ga-mediated allylation of (R)-2,3- cyclohexylideneglyceraldehyde as the key step. The synthesis deviates significantly from the previous syntheses of the ¹⁸F-FLT precursors wherein the expensive starting material, thymidine was used.