Synthetic cannabinoid metabolites with a 5F-4OH pentyl side chain are of great interest, and several synthetic methods have been developed for the synthesis of these types of metabolites in the literature, which is either lengthy or inappropriate for upscaling. Herein, a straightforward method has been developed and reported for the synthesis of a key intermediate in four steps with an overall yield of 49% on a multigram scale, and its application in the synthesis of nine potential metabolites of synthetic cannabinoids with a 5F-4OH pentyl side chain.