Hypercoordinate iodine(III) promoted reactions and catalysis: an update on current mechanistic understanding

Abstract

Mild and environment friendly hypercoordinate iodine compounds exhibit promising reactivities resembling that of transition metal catalysts. Hypercoordinate iodine reagents or catalysts are increasingly been employed in contemporary organic synthesis. However, mechanistic insights on such reactions continue to remain rather limited. Recent advances in the mechanistic understanding on a selected set of reactions involving hypercoordinate iodine form the main theme of this review. An overview of bonding, reactivity, and mechanistic insights on iodine(III) reactions such as α-functionalization of carbonyl compounds, alkynylation, amination, C H functionalization, phenol dearomatization, and trifluoromethylation have been described. In keeping with the current practices in mechanistic studies, we have maintained an interdisciplinary flavor in this compilation by providing a balanced view of computational and experimental understanding on the burgeoning domain of hypercoordinate iodine mediated reactions and catalysis. FIGURE 1 | Molecular orbital (MO) diagram for three-center-fourelectron (3c-4e) bond in hypercoordinate iodine compound RIL 2 . SCHEME 1 (a) General representation of α-tosyloxylation ketone catalyzed by Koser's reagent. (b) General mechanism for the α-tosyloxylation ketone. (c) Commonly employed iodoarenes in α-tosyloxylation. Overview wires.wiley.com/compmolsci SCHEME 2 (a) Effect of different substituents on the catalytic activity of iodoaryl in α-tosyloxylation. (b) Effect of different substituents on dihedral angle θ(C1-C2-I3-O4). (c) Formation of iodono intermediate 4 and the related ΔG rxn . WIREs Computational Molecular Science Hypercoordinate iodine(III) promoted reactions and catalysis Volume 7,

Mechanism and Origins of Chemo- and Stereoselectivities of Aryl Iodide-Catalyzed Asymmetric Difluorinations of β-Substituted Styrenes

“…More accurate electronic energies were obtained by single point energy calculations at the SMD-M06–2X/6–311++G(d, p)+SDD(I) 19 level of theory. 20 A number of previous computational studies of hypervalent iodine-mediated reactions have employed the M06–2X functional. 21…”

A hypervalent and cubically coordinated molecular phase of IF8predicted at high pressure

“…The ability of iodine to engage in hypercoordination allows fabrication of compounds that are potential substitutes for transition metal-based catalysts 9,10. Commercially available hypercoordinated iodine compounds have shown promise for mild and highly selective oxidizing ability and environmentally benign catalysis 11–14…”

Hypercoordinate iodine for catalytic asymmetric diamination of styrene: insights into the mechanism, role of solvent, and stereoinduction

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