Halogen complexes asymmetry

Haber process, 116 Hafnium complexes alkyl alkoxy reactions, 358 phthalocyanines, 865 porphyrins, 823 pseudohalides, 228 Hafnium(IV) complexes cupferron, 512 Haloarsine compounds, 1004 Halogen complexes, 675-687 bridge systems, 677-684 asymmetry, 678 theoretical studies, 682 double bridged, 681... 

Table 5 lists parameters for a selection of halogen-bridged species with this type of asymmetry. The effect of multiply bonded oxygen is larger than the other ligands listed, and the comparison of oxide as part of the ligand, in the pentane-2,4-dionate complex,27 where the asymmetric Mo—Cl distances only differ by 0.091 A, with the oxide trichloride, where the difference is 0.44 A, is particularly striking. 

Asymmetric ene Reaction In 1988 Yamamoto and coworkers provided the first indication that asymmetry in ene-reactions could be induced by catalytic amounts of chiral Lewis acids in the presence of 4-A molecular sieves (Scheme 6.64) [88]. They described the first example of asymmetric ene-reaction between prochiral, halogenated aldehydes and alkenes catalyzed by chiral binaphthol-derived aluminum complexes. The hindered 3,3-silyl substituents in the chiral catalyst are essential to achieve good enantioselectivity and high yield. In fact, the use of a catalyst derived from MesAl and 3,3 -biphenylbinaphthol led to the racemic product in a low yield. 

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