We report palladium‐catalyzed cross‐coupling reactions of chiral secondary non‐stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides α‐chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76 % for 3 reaction steps). The configurational stability of these chiral non‐stabilized dialkylzinc reagents was determined and exceeded several hours at 25 °C. DFT calculations were performed to rationalize the stereoretention during the catalytic cycle. Furthermore, the cross‐coupling reaction was applied in an efficient total synthesis of the sesquiterpenes (S)‐ and (R)‐curcumene with control of the absolute stereochemistry.

A general preparation of enantiomerically and diastereomerically enriched secondary alkylmagnesium reagents was reported as well as their use for performing highly stereoselective transition-metal free electrophilic aminations leading to α-chiral amines...

The preparation of chiral non-stabilized open-chain alkyl­lithium reagents prepared from the corresponding chiral secondary alkyl iodides and their subsequent transmetalation to the corresponding secondary alkylcopper or alkylzinc derivatives is reviewed. These new organometallic reagents allow the stereoselective preparation of a broad range of chiral molecules.1 Introduction2 Stereoselective Preparation of Secondary Alkyllithiums3 Preparation of Stereodefined Secondary Alkylcopper Reagents4 Preparation of Stereodefined Secondary Alkylzinc Derivatives and Their Stereoselective Cross-Coupling with Alkenyl and Aryl Halides­5 Conclusion

Polyfunctional organometallics of magnesium and zinc are readily prepared from organic halides via a direct metal insertion in the presence of LiCl or a Br/Mg-exchange using iPrMgCl·LiCl (turbo-Grignard) or related...

A new method for regioselective zincations of challenging N-heterocyclic substrates such as pyrimidines and pyridazine was reported using bimetallic bases TMPZnX•LiX (TMP = 2,2,6,6-tetramethylpiperidyl; X = Cl, Br). Reactions occurred under mild conditions (25-70 °C, using 1.75 equivalents of base without additives), furnishing 2-zincated pyrimidines and 3-zincated pyridazine, which were then trapped with a variety of electrophiles. Contrasting with other s-block metalating systems, which lack selectivity in their reactions even when operating at low temperatures, these mixed Li/Zn bases enabled unprecedented regioselectivities that cannot be replicated by either LiTMP nor Zn(TMP) 2 on their own. Spectroscopic and structural interrogations of organometallic intermediates involved in these reactions have shed light on the complex constitution of reaction mixtures and the origins of their special reactivities.