Chiral clusters sources

Carbohydrates, similarly to peptides, are natural sources of chirality and also offer a wide range of ncm-covalent interactions. Molecular recognition of carbohydrates by biological receptors mediates a variety of physiologically relevant processes, including recruitment of leucocytes to inflammatory sites, clearance of glycoproteins from the circulatory system, cell interactions in the immune system, as well as adhesion of bacteria or viruses to host cells. It has been shown that multivalency is especially important for carbohydrate-receptor interactions. The glycoside cluster... 

Successful conditions for intermolecular carbene insertions into alkane C-H bonds with diazo esters have been reported under Ag(I) and Ir(III) catalyses. While the argen-tate trinuclear cluster (90) has been shown to catalytically promote such C-H insertion with ethyl diazoacetate, " Ir(III)-based porphyrin catalyst (91) appeared much more efficient using bulky methyl 2-phenyldiazoacetate as an alternative carbene source. Ir(III)-based porphyrin analogue (92) bearing chiral arms promotes carbene insertion with up to 98% yield in an asymmetric manner (up to 98% ee). ... 

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