In recent years, C−H bond functionalization has emerged as a pivotal tool for late‐stage functionalization of complex natural products for the synthesis of potent biologically active derivatives. Artemisinin and its C‐12 functionalized semi‐synthetic derivatives are well‐known clinically used anti‐malarial drugs due to the presence of the essential 1,2,4‐trioxane pharmacophore. However, in the wake of parasite developing resistance against artemisinin‐based drugs, we conceptualized the synthesis of C‐13 functionalized artemisinin derivatives as new antimalarials. In this regard, we envisaged that artemisinic acid could be a suitable precursor for the synthesis of C‐13 functionalized artemisinin derivatives. Herein, we report C‐13 arylation of artemisinic acid, a sesquiterpene acid and our attempts towards synthesis of C‐13 arylated artemisinin derivatives. However, all our efforts resulted in the formation of a novel ring‐contracted rearranged product. Additionally, we have extended our developed protocol for C‐13 arylation of arteannuin B, a sesquiterpene lactone epoxide considered to be the biogenetic precursor of artemisinic acid. Indeed, the synthesis of C‐13 arylated arteannuin B renders our developed protocol to be effective in sesquiterpene lactone as well.