Unravelling the hidden link of lithium halides and application in the synthesis of organocuprates

Abstract

As a versatile metal, copper has demonstrated a wide application in acting as both organometallic reagent and catalyst. Organocuprates are among the most used organometallic reagents in the formation of new carbon–carbon bonds in organic synthesis. Therefore, revealing the real structures of organocuprates in solution is crucial to provide insights into the reactivity of organocuprates. Here we provide several important insights into organocuprate chemistry. The main finding contains the following aspects. The Cu(0) particles were detected via the reduction of CuX by nBuLi or PhLi. The Cu(II) precursors CuX2 (X=Cl, Br) could be used for the preparation of Gilman reagents. In addition, we provide direct evidence for the role and effect of LiX in organocuprate synthesis. Moreover, the EXAFS spectrum provides direct evidence for the exact structure of Li+ CuX2− ate complex in solution. This work not only sheds important light on the role of LiX in the formation of organocuprates but also reports two new routes for organocuprate synthesis.

Tuning radical reactivity for selective radical/radical cross-coupling

“…Based on previous researches in X-ray absorption fine structure (XAFS), we found that the equilibrium between organocuprates and radicals could serve as persistent radical [20][21][22]. This reveals that transient radical could be translated into persistent radical in special conditions.…”

Visible-Light Mediated Oxidative C–H/N–H Cross-Coupling between Tetrahydrofuran and Azoles Using Air

“…Visible light photoredox catalysis has emerged as a powerful technique in organic synthesis in recent years, providing a mild condition for organic transformation. In continuation of our interest in the development of C–H activation/functionalization methods and mechanistic studies, seeking a mild and green way is always under operation in our lab. Herein, we report a simple and mild metal-free catalytic oxidative amination approach via α-C­(sp 3 )-H activation of tetrahydrofuran mediated by visible-light using air as benign oxidant (Scheme ).…”

Anion redox as a means to derive layered manganese oxychalcogenides with exotic intergrowth structures

“…In addition, disulfiram’s covalently bonded skeleton made of C, N, S and non-acidic protons is less likely to destroy the main phase compared to reagents made of halogens, nitronium or acidic protons. We also tried to dissolve Cu + cations at Step 1 as organolithium cuprates 26 before they are reduced to elemental Cu 0 but these attempts were so far unsuccessful. Nevertheless, the one-pot removal of Cu would significantly simplify the synthetic procedure and therefore this will be one of our next challenges in synthetic methodology.…”