Palladium-catalysed ortho-arylation of carbamate-protected phenols

Abstract

The carbamate (-O2CNR2) function is an excellent directing group for palladium-catalysed direct arylation reactions giving both protected or free mono- or di-substituted phenols, as well as an example of a dibenzopyranone, depending on coupling partners (aryl iodides or diaryliodonium salts) and conditions.

Diaryliodonium Salts in Organic Syntheses: A Useful Compound Class for Novel Arylation Strategies

“…99 The reported results revealed the opportunity of a step-economical arylation of phenol derivatives in a solvent-free method using microwave irradiation. One year later, the authors presented a synthetically expanded new procedure to perform the arylation of aromatic carbamates.…”

“…The electrophilic species induces intramolecular aromatic electrophilic substitution providing the appropriate heterocyclic systems such as quinoline (96) and quinazoline (97) 79 (99) was developed in our group. The procedure is based on the copper catalyzed oxidative ring closure of arylpropynyloxy-benzonitriles (98) with diaryliodonium salts.…”

Copper-Catalyzed Diarylation of Activated Alkenes with Diaryliodonium Salts

“…5 2i, 2j, 2k, 2l, 2m was prepared from corresponding iodobenzenes and mesitylene in the presence of mCPBA and TfOH. [6][7][8][9]…”

Transition Metal‐Catalyzed Directing‐Group‐Assisted C−H Activation of Phenols

“…The carbamate functional group (−O 2 CNR 2 ) is easily installed on and removed from phenol substrates, it is also regarded as an effective directing group to achieve the ortho ‐functionalization of phenol derivatives. In 2009, Bedford and co‐workers reported a Pd‐catalyzed ortho ‐arylation of carbamate‐protected phenols with aryl iodides to synthesize mono‐ and diarylated phenols (Scheme ) . In addition, the diaryliodonium salt was also found to be an efficient arylating reagent, affording ortho mono‐arylated phenols with liberation of the carbamate group.…”

“…In 2009, Bedforda nd co-workersr eported aP d-catalyzed ortho-arylation of carbamate-protected phenols with aryl iodides to synthesize mono-and diarylated phenols (Scheme 18). [25] In addition, the diaryliodonium salt was also found to be an efficient arylating reagent, affording ortho mono-arylatedp henols with liberation of the carbamate group.…”