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).

In the footsteps of Victor Grignard: The simple LiCl‐mediated insertion of magnesium into aryl chlorides and bromides at moderate temperatures leads to functionalized organomagnesium reagents (see scheme). An unprecedented range of functional groups may be present in the substrates (e.g. CN, CO2R, OTs, OBoc; Ts=p‐toluenesulfonyl, Boc=tert‐butylcarbonyloxy).

The synthesis and characterization of a new mesoporous Covalent Organic Framework BTP-COF is described, the latter having fully accessible pores with an open diameter of 4.0 nm.

The presence of LiCl considerably facilitates the insertion of magnesium into various aromatic and heterocyclic bromides. Several functional groups, such as -OBoc, -OTs, -Cl, -F, -CF(3), -OMe, -NMe(2), and -N(2)NR(2), are well tolerated. The presence of a cyano group leads in some cases to competitive reduction of the organic halide to the corresponding ArH compound. The presence of sensitive groups such as methyl or ethyl ester is tolerated upon in situ trapping of the intermediate magnesium reagent with ZnCl(2). This method can also be applied to the preparation of functionalized benzylic zinc reagents from benzylic chlorides. In the case of di- or tribromoaryl derivatives, directing groups such as -OPiv, -OTs, -N(2)NR(2), or -OAc orient the zinc insertion (Zn/LiCl) to the ortho-position, while the reaction with Mg/LiCl or Mg/LiCl/ZnCl(2) leads to regioselective insertion into the para-carbon-bromine bond. Large-scale experiments (20-100 mmol) for all of the metalation procedures are described.

Stereoselective functionalizations of organic molecules are of great importance to modern synthesis. A stereoselective preparation of pharmaceutically active molecules is often required to ensure the appropriate biological activity. Thereby, diastereoselective methods represent valuable tools for an efficient set-up of multiple stereocentres. In this article, highly diastereoselective Csp(3) Negishi cross-couplings of various cycloalkylzinc reagents with aryl halides are reported. In all cases, the thermodynamically most-stable stereoisomer was obtained. Remarkably, this diastereoselective coupling was successful not only for 1,2-substituted cyclic systems, but also for 1,3- and 1,4-substituted cyclohexylzinc reagents. The origin of this remote stereocontrol was investigated by NMR experiments and density functional theory calculations. A detailed mechanism based on these experimental and theoretical data is proposed.

A general, transition-metal-free, highly stereoselective cross-coupling reaction between glycosyl bromides and various arylzinc reagents leading to β-arylated glycosides is reported. The stereoselectivity of the reaction is explained by invoking anchimeric assistance via a bicyclic intermediate. Stereochemical probes confirm the participation of the 2-pivaloyloxy group. Finally, this new method was applied to a short and efficient stereoselective synthesis of Dapagliflozin and Canagliflozin.

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Eine Menge Verbindungen: Ein breites Spektrum an funktionalisierten (hetero)aromatischen und aliphatischen Zinkreagentien kann problemlos in Tetrahydrofuran hergestellt werden. Zur Anwendung kommt dabei eine durch Lithiumchlorid vermittelte Zinkinsertion (siehe Schema; All=Allyl).