Barbier-type reactions intermolecular

Additionally, various intra- and intermolecular iron-catalyzed Barbier-type reactions of organosamarium com-pounds and carbonyl electrophiles have been reported by Molander and co-workers. 

The mechanism of the intermolecular Sml2-promoted Barbier-type reaction is still open to debate. Direct Ss2-type displacement of the halide by a ketyl or a ketyl dianion is unlikely, since optically active... 

Intermolecular Barbier-type reactions are reportedly not possible when Ybh is utilized as the reductant. However, intramolecular versions of the reaction proceed smoothly. Both five- and six-mem-bered rings can be generated in this process, and in some cases the observed diastereoselectivities exceed those achieved with Smh (equation 97). Unfortunately, diastereoselectivity is not always high nor predictable, and thus mixtures of cis and trans bicyclic alcohols are usually generated. 

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