α‐Arylation by Rearrangement: On the Reaction of Enolates with Diaryliodonium Salts

Abstract

Surprising equilibration: A new mechanism for the title reaction is supported by DFT calculations and experimental observations. The CI and OI intermediates are isoenergetic and equilibrate quickly. Thus, any chiral information induced in the initial complex will be destroyed. In the final CC bond‐forming step, a [2,3]‐rearrangement from the OI bonded intermediate is slightly preferred over the [1,2]‐elimination from the CI bonded isomer (see scheme).

Metal-Free N-Arylation of Secondary Amides at Room Temperature

“…24 The facile formation of highly hindered tertiary amides in this protocol might indicate that intermediate B is important in the arylation, and this mechanism will be investigated further.…”

The emergence of sulfoxide and iodonio-based redox arylation as a synthetic tool

“…Interestingly, iodonium O-enolate intermediates have been invoked with both classes of hypervalent reagents, and the difference, therefore, appears to reside in the preferred class of rearrangement for each type of intermediate. 23 Thus, for the diaryliodonium species a [1,2] rearrangement dominates leading to an ipso substitution, while in the present case a [3,3] rearrangement leads to ortho products (Scheme 22).…”

Understanding and Exploitation of Neighboring Heteroatom Effect for the Mild N-Arylation of Heterocycles with Diaryliodonium Salts under Aqueous Conditions: A Theoretical and Experimental Mechanistic Study

“…24 Earlier calculations predicted that the dissociated state is less stable by 1.7 kcal/mol when the solvent is THF. 10 This discrepancy points to a role of the solvent in the mechanism. We have chosen the reaction between 3,5-diphenylpyrazole (1a) and diphenyliodonium triflate (2a) as our model system.…”

“…However, we note that further optimization of the conditions for the new substrates is necessary for amplifying the potential of this synthetic strategy. 10,14 or it can be assumed via the iminol tautomer. 16 …”