Synthetic strategies toward 3-fluoroazetidine-3-carboxylic acid, a new cyclic fluorinated β- amino acid with high potential as building block in medicinal chemistry, were evaluated. The successful pathway includes the bromofluorination of N-(diphenylmethylidene)-2-(4- methoxyphenoxymethyl)-2-propenylamine, yielding 1-diphenylmethyl-3-hydroxymethyl-3- fluoroazetidine after reduction of the imino bond, ring closure, and removal of the 4- ...