Reactivity of Acceptor-Acceptor Diazo-Pyrazolones with Allyl Thioethers under Visible Light: Access to Homoallyl and Bis-Homoallyl Sulfides, Spiropyrazolones-Pesticide Analogues and Photo-Flow Synthesis

Pyrazolone framework has been greatly explored for various applications owing to their presence in many bioactive compounds. The novel reactivity of less selective and more reactive acceptor-acceptor kind of diazo pyrazolone (DIPOL) has been explored under visible light for the first time. We have successfully demonstrated the reaction of DIPOL and different allyl thioethers under blue light to construct a wide variety of products including pesticidal analogue exclusively in excellent chemo-selectivities in good to excellent yields. Moreover, the possible side products emanating from ketene were not observed. This protocol works smoothly in environmentally benign solvent under inert free condition. The practicality of the protocol has been extended to photo-flow reaction and also the reaction works smoothly under the direct exposure of sunlight.