Triarylborane-Catalyzed Alkenylation Reactions of Aryl Esters with Diazo Compounds.

Ayan Dasgupta,Alireza Ariafard,Rasool Babaahmadi,Lukas Gierlichs,Katarína Stefkova,Rebecca L Melen

doi:10.1002/anie.202007176

Abstract

Herein we report a facile, mild reaction protocol to form carbon–carbon bonds in the absence of transition metal catalysts. We demonstrate the metal‐free alkenylation reactions of aryl esters with α‐diazoesters to give highly functionalized enyne products. Catalytic amounts of tris(pentafluorophenyl)borane (10–20 mol %) are employed to afford the C=C coupled products (31 examples) in good to excellent yields (36–87 %). DFT studies were used to elucidate the mechanism for this alkenylation reaction.

Highlights

We report a facile, mild reaction protocol to form carbon–carbon bonds in the absence of transition metal catalysts
We investigate the alkenylation of benzylic sp3 centers using tris(pentafluorophenyl)borane [B(C6F5)3] as the catalyst (Figure 1 d) as a new route to generate conjugated organic compounds
We further examined the scope of this methodology in fluorobenzoic acid to generate the C=C coupled enyne reactions with the unsymmetrical a-aryl-diazoesters methyl 2

Summary

Introduction

We report a facile, mild reaction protocol to form carbon–carbon bonds in the absence of transition metal catalysts. In the absence of a borane catalyst no reaction occurred after 22 h at 65 8C (Table 1, entry 1).

Results

Conclusion