Water extract of pomegranate ash-I2 as sustainable system for external oxidant/metal/catalyst-free oxidative iodination of (hetero)arenes

Utilization of waste-derived materials for industrially pertinent chemical transformations is highly challenging and offers sustainable solution to waste management. Despite several difficulties in the manufacture of aryl iodides (AIs), which are the fundamental substrates in organic synthesis, we report here, an added oxidant/metal/catalyst/additive and problematic solvent-free versatile and straightforward protocol for the synthesis of AIs using molecular iodine (I-2) in water extract of pomegranate ash (WEPA). These transformations were performed at room temperature (rt) and the reactions takes place in 5-20 min to give 83-99% yields of AIs. WEPA was characterized by using XPS, EDX, XRF, XRD, and FTIR analysis and a plausible mechanism has been established based on these analyses along with some control experiments. Further, the products were purified by recrystallization technique. This work with intrinsic sustainability, high substrate feasibility, utilization of biorenewable catalystytic media, ease of execution and separation of products, and added oxidant/catalyst/metal and additive-free conditions may become one among the forefront sustainable procedures in making AIs. The use of waste-derived WEPA as catalystytic media for this iodination is the novelty of this method and may be used these AIs for further in-process transformations (e.g. cross-couplings, nucleophilic reactions, etc.) to access fine chemicals.

Automated summary

This study presents a straightforward and efficient method for synthesizing aryl iodides using molecular iodine in water extract of pomegranate ash, with mild reaction conditions and high yields, which can be further utilized for the preparation of fine chemicals.