Chiral cavities asymmetric syntheses

Owing to their size and the feasibility of controlling the dendrimer structure and globular morphology via their synthesis, dendrimers with chiral branching scaffold are of interest as potential protein mimics. In addition, the introduction of chiral branching units or spacers into the molecular scaffold should lead to the development of non-symmetrical macromolecular conformations and provide chiral cavities for asymmetrical catalysis or chiral recognition processes. 

Finally, the catalytic activity of chiral polymer poly(+)(MASBF)4PFeCl bearing four chiral SBF units in meso position of the porphyrin ring was investigated. However, this first example of chiral porphyrin based on SBF scaffold does not display any enantioselectivity (ee < 5 %) and even displays a low epoxidafion yield of 30 % [73]. Different alkenes such as styrene, 4-chlorostyrene, 4-methylslyrene or cyclooctene were tested but no chiral induction was observed. This might be due to the structure of the SBF unit, which leads in both monomer and polymer to a large chiral cavity and thus no asymmetric synthesis was observed. 

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