Synthesis of Lithium Boracarbonate Ion Pairs by Copper‐Catalyzed Multi‐Component Coupling of Carbon Dioxide, Diboron, and Aldehydes

Abstract

The catalytic selective multi-component coupling of CO2 , bis(pinacolato)diboron, LiOtBu, and a wide range of aldehydes has been achieved for the first time by using an NHC-copper catalyst. This transformation has efficiently afforded a series of novel lithium cyclic boracarbonate ion pair compounds in high yields from readily available starting materials. This protocol has not only provided a new catalytic process for the utilization of CO2 , but it has also constituted a novel route for the efficient synthesis of a new class of lithium borate compounds that might be of interest as potential electrolyte candidates for lithium ion batteries.

Beneficial Effect of a Secondary Ligand on the Catalytic Difunctionalization of Vinyl Arenes with Boron and CO2

“…These results suggest that salt metathesis (Step IV) and formation of [Cu]−Bpin (Step I) are not impacted by PPh 3 . Preliminary evidence from in situ infrared spectroscopy supports the formation of metal‐carbonate species during the reaction, which was also suggested by Hou in a similar reaction with aldehyde substrates . Thus, the role of PPh 3 may involve trapping of copper catalyst decomposition products as organic carbonates as observed by Saegusa 40 years ago…”

Catalytic Intermolecular Dicarbofunctionalization of Styrenes with CO2 and Radical Precursors

“…As part of our ongoing interest in nickel-catalyzed reductive carboxylation techniques with CO 2 , [6,7] we questioned whether an ew design principle within the carboxylation arena, with improved flexibility and versatility en route to phenyl acetic acids,c ould be implemented. In particular, we speculated that aredox-neutral mechanism [8] might enable an intermolecular dicarbofunctionalization of styrenes with simple radical precursors by the intermediacyo fA (Scheme 1, bottom), thus offering new vistas for an atomeconomical incorporation of CO 2 into organic matter.…”

Carboxylation Reactions with Carbon Dioxide Using N‐Heterocyclic Carbene‐Copper Catalysts

“…We have accomplished the first one‐pot multi‐component coupling reaction of CO 2 , B 2 (pin) 2 , LiO t Bu, and various aldehydes, enabling highly efficient and selective preparation of novel lithium cyclic boracarbonate ion pair compounds which feature a unique cyclic carbonate structure fused with a pinacolatoborate moiety . We examined various NHC‐copper catalysts for the reaction of benzaldehyde with B 2 (pin) 2 (1.0 equivalent) and LiO t Bu (1.1 equivalent) under a CO 2 atmosphere.…”