Polyfunctionalized organometallic reagents are ubiquitous intermediates in modern organic chemistry.[1] One of the best methods for preparing these reagents is the halogen-metal exchange reaction. [1, 2] Whereas Br/Li exchange is fast and occurs at low temperatures, the corresponding Br/Mg exchange [3] is considerably slower, which limits its synthetic application for several reasons: 1) The exchange requires higher reaction temperatures and is therefore not compatible with many functional groups; 2) The slow Br/Mg exchange especially for electron-rich aromatic bromides is in competition with the elimination of HBr from the alkyl bromide also produced during the reaction (usually isopropyl bromide) and therefore results in low yields. A catalyzed version of the Br/Mg exchange reaction would be a highly desirable process.Recently we found that I/Zn exchange can be converted into a catalytic reaction by the addition of [Li(acac)] (10 mol %, acac = acetylacetonato) to an aryl iodide and iPr 2 Zn.[4] Encouraged by these results, we have examined the effect of salt additives on the rate of Br/Mg exchange.[3] We chose the electron-rich and therefore unreactive 4-bromoanisole (1 a) and treated it with iPrMgCl (1.05 equiv; 1m in THF) in the presence of several lithium salts. A slow Br/Mg exchange occurred in the absence of additives, leading to only 18 % conversion after 68 h at room temperature (entry 1, Table 1). Whereas the addition of LiBF 4 resulted in several products (entry 2), the addition of LiBr, LiI, and LiClO 4 gave minor improvements (38-40 % conversion; entries 3-5). On the other hand, the addition of LiCl (1 equiv) led to a spectacular rate increase and 70 % conversion (entry 6). The addition of smaller amounts of LiCl resulted in lower conversion (entries 7 and 8), whereas larger quantities did not lead to further rate increases (entries 9 and 10). When a

An environmentally benign surfactant (“TPGS-750-M”), a diester composed of racemic α-tocopherol, MPEG-750, and succinic acid, has been designed and readily prepared as an effective nanomicelle-forming species for general use in metal-catalyzed cross-coupling reactions in water. Several “name” reactions, including Heck, Suzuki-Miyaura, Sonogashira, and Negishi-like couplings have been studied using this technology, as have aminations, C-H activations, and olefin metathesis reactions. Physical data in the form of DLS and cryo-TEM measurements suggest that particle size and shape are key elements in achieving high levels of conversion and hence, good isolated yields of products. This new amphiphile will soon be commercially available.

Two are better than one: Mixed lithium‐magnesium complexes of the type R2NMgCl⋅LiCl are kinetically highly active bases that convert a range of polyfunctional aromatic and heteroaromatic substrates into the corresponding magnesiated derivatives with high regioselectivity.

Insider dealing: A wide range of polyfunctional (hetero)aromatic and aliphatic zinc reagents can be easily prepared in THF. The compounds are formed by a Zn insertion reaction mediated by the addition of LiCl (see scheme; All=allyl).

Easy‐to‐prepare solutions of LnCl3⋅2 LiCl (Ln=La, Ce, Nd) (0.3–0.5 M in THF) are a unique source of soluble lanthanide salts with versatile applications in organic synthesis. These salts can serve as promoters or catalysts for the addition of organometallic compounds to sterically hindered, enolizable or α,β‐unsaturated ketones or imines.