Iridium‐Catalyzed α‐Selective Arylation of Styrenes by Dual C−H Functionalization

Phillippa Cooper,Giacomo E M Crisenza,John F Bower,Lyman J Feron

doi:10.1002/ange.201808299

Phillippa Cooper, Giacomo E M Crisenza + Show 2 more

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https://doi.org/10.1002/ange.201808299

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Abstract

AbstractAn IrI‐system modified with a ferrocene derived bisphosphine ligand promotes α‐selective arylation of styrenes by dual C−H functionalization. These studies offer a regioisomeric alternative to the Pd‐catalyzed Fujiwara–Moritani reaction.

Highlights

We have previously described Ir-catalyzed branch selective hydroarylations of styrenes with acetanilides 1 (DG = NHAc, Scheme 1B).[8a]. These processes were posited to occur via a sequence of carbonyl directed C-H activation, alkene hydrometallation and C-C reductive elimination
We show that modification of the Ir-center with specific bisphosphine ligands alters the reaction outcome to provide a method for the α-selective arylation of styrenes (1 to 4)
This new dual C-H functionalization method is regioisomeric with respect to the Fujiwara-Moritani and Heck reactions,[1,5] and previous Ircatalyzed C-H alkenylation processes,[9,10] thereby providing proof-of-concept for a unique approach to the α-arylation of

Summary

Introduction

We have previously described Ir-catalyzed branch selective hydroarylations of styrenes with acetanilides 1 (DG = NHAc, Scheme 1B).[8a] These processes were posited to occur via a sequence of carbonyl directed C-H activation (to I), alkene hydrometallation (to II) and C-C reductive elimination (to 3). We show that modification of the Ir-center with specific bisphosphine ligands alters the reaction outcome to provide a method for the α-selective arylation of styrenes (1 to 4).

Results

Conclusion