No abstract

The presence of a remote unsaturation (double bond, carbonyl group, cyano group) in an alkyl halide facilitates its cross-coupling reaction with various diorganozincs in the presence of Ni(acac)(2) (7.5-10 mol % in THF/NMP mixtures). These results were used to develop a new general cross-coupling reaction between functionalized diorganozincs and alkyl iodides using m- or p-trifluoromethylstyrene as a reaction promotor and Ni(acac)(2) as a catalyst (7.5-10 mol %; -35 degrees C, 5-10 h) leading to a broad range of polyfunctional cross-coupling products.

Since the pioneering work of Wurtz, cross-couplings between sp carbon centers have had the reputation of being difficult. In the presence of a catalytic amount of m-trifluoromethylstyrene, an efficient cross-coupling reaction takes place between polyfunctional primary alkyl iodides and diorganozinc compounds [Eq. (a)] to give a general catalytic cross-coupling between sp carbon centers. Piv=pivaloyl; Pent = pentyl; acac = acetalacetonate; NMP = N-methylpyrrolidone.

Seit den Pionierarbeiten von Wurtz gelten Kreuzkupplungen zwischen C‐sp3‐Zentren als problematisch – in Gegenwart katalytischer Mengen m‐Trifluormethylstyrol findet jedoch eine effiziente Kreuzkupplung zwischen funktionalisierten, primären Iodalkanen und funktionalisierten Dialkylzinkverbindungen statt [Gl. (a)]. Die Kreuzkupplung von C‐sp3‐Zentren wird damit allgemein auf katalytischem Wege möglich. Piv=Pivaloyl; Pent=Pentyl; acac=Acetylacetonat; NMP=N‐Methylpyrrolidon.