Starting computational study of the chlorination mechanism reaction of 2-Naphthol with PIDA and AlCl<sub>3</sub> via PhICl<sub>2</sub> formation as a chlorinating reagent.

Abstract

Recently we described the first chlorination of mono-and bis-annular phenols by using the non-described PIFA/AlCl3 system. Looking for a mechanistic pathway to elucidate this novel procedure, we decided to explore all the plausible path. In order to determine the best energy profile which, provide us the lower-in-energy mechanism, herein we present an initial computational study for the chlorination reaction of 2-naphthol exploring PIDA [diacetoxyiodo(benzene)] and AlCl3. The developed first mechanism that considers the PhICl2 formation as the plausible chlorinating intermediate was analized by DFT calculations at the (SMD:acetonitrile)ω-B97XD/(6-311G(d,p),LANL08d)//ω-B97XD/6-31G(d) level indicated that the reaction proceed through a cationic pathway.

Divergent role of PIDA and PIFA in the AlX3 (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

“…Hypervalent iodine(III) reagents have gained attention as strong oxidants with a low toxicity [ 1 – 8 ] and due to the ability to mimic reactivity [ 9 ] usually associated with transition metals [ 10 – 11 ]. Iodine(III) compounds have been used for the formation of different bond types, such as C–C [ 12 – 13 ], C–O [ 14 – 15 ], C–N [ 16 ], C–S [ 17 ], C–CN [ 18 ], C–F [ 19 – 21 ], C–I [ 22 – 23 ], C–NO 2 [ 24 – 25 ] and, in the context of this work, C–X (X = Cl, Br) [ 26 – 31 ]. So far, different protocols for the halogenation of arenes using iodine(III) reagents have been described, mainly using (diacetoxyiodo)benzene (PIDA)/TMSCl, PIDA/TMSBr [ 32 ], and [bis(trifluoroacetoxy)iodo]benzene (PIFA)/TMSBr [ 33 ].…”