Bromine complexes single bridges

NMR-spectroscopic studies and a single crystal X-ray structure determination of the reduced Co / form of 100 revealed the presence of a bridging 2,3-dibromo-3-phenyl-propionato ligand (threo dl pair). The complex bearing the erythro form of 2,3-dibromo-3-phenyl-propionate is only produced in minor yields <3%. Therefore, the bromination of the encapsulated alkene is a highly diastereoselective syu-addition. This is rather... 

Reaction of 3-hydroxy-oxonene 103 with the complex of bromine and l,2-bis(diphenylphosphino)ethane resulted in an expected mixture of brominated compounds 105 and 106, along with single stereoisomer of oxocene 107, probably due to the formation of the bridged oxonium cation and its two different directions of the reaction with bromide anion (Scheme 17, Section 14.10.5.5.3) <1995TL8263>. 

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