Metal-organic porous materials are receiving growing attention [1] because of their potential applications in gas storage, [2] separation, [3] and many other areas. [4] Although catalysis is one of the most promising applications of such materials, only a handful of examples have been reported to date. [5] Furthermore, despite considerable efforts, attempts to synthesize robust, homochiral metal-organic porous materials capable of enantioselective separation and/or catalysis have met with only limited success. [6,7] Most homochiral metalorganic frameworks are not robust enough to show permanent porosity, nor porous enough to be useful for selective sorption or catalytic transformation of organic molecules. Therefore, the synthesis of robust homochiral metal-organic frameworks with potential for application is still challenging. For the synthesis of homochiral metal-organic open frameworks, two general approaches have been taken: 1) use of a rigid homochiral organic ligand as a spacer to link adjacent metal centers or secondary building units (SBUs), [5b-d, 7] and 2) use of a homochiral ligand as an auxiliary pendant which does not directly participate in the formation of a framework backbone, but forces the framework to adopt a specific chiral topology.[3d] Herein, we introduce another rational approach to the synthesis of homochiral metal-organic frameworks. A metal ion and a readily available homochiral organic ligand are used to form homochiral SBUs, which in turn, are linked together by rigid spacers to build a network structure, in a one-pot reaction (Scheme 1).[8] With a judicious choice of metal ion, homochiral organic molecule, and rigid polytopic linker (that is, a connector with more than one metal coordination site), this approach allows us to synthesize metal-organic open frameworks with stable chiral pores. Herein, we report a new homochiral metal-organic material that has permanent porosity, size-and enantioselective sorption properties, and catalytic activity.[9]

Chiral bipyrrolidine based iron and manganese complexes [((S,S)-pdp)MII(OTf)2] catalyze the asymmetric epoxidation of various olefins with H2O2 in the presence of carboxylic acid additives with high efficiency (up to 1000 turnover number (TON)) and selectivity (up to 100%), and with good to high enantioselectivity (up to 93% enantiomeric excess (ee)). The enantioselectivity increases with growing steric demand of the acid. On the basis of the electron paramagnetic resonance (EPR) spectroscopy and enantioselectivity studies, the active oxygen-transferring species of the above systems can be identified as structurally similar oxometal(V) species of the type [((S,S)-pdp)MVO(OCOR)]2+ (M = Fe, Mn; R = alkyl).

The discovery of simple and efficient catalyst systems for the asymmetric oxofunctionalization of hydrocarbons is a challenging task of catalytic chemistry. In this paper, we give an overview of catalyst systems capable of conducting asymmetric oxygenative transformations of organic molecules and, in line with the major trend to sustainability, relying on green oxidants HO and O as the ultimate oxygen source. The full historical period of asymmetric oxidation catalysis (1970 to the present day) is covered; both transition-metal-based and organocatalytic systems are considered. The focus of this review is the catalytic properties of the existing catalyst systems, in particular stereoselectivity, activity, efficiency, and synthetic outlook. At the same time, mechanistic peculiarities of stereoselective oxygen transfer are given attention.

(R)- and (S)- enantiomers of alkyl aryl sulfoxides can be obtained by chromatographic resolution of the racemic mixtures of the sulfoxides on a microporous homochiral Zn-organic polymer or by simultaneous catalytic oxidation of the corresponding sulfides with H2O2 and enantioselective chromatographic resolution of the resulting sulfoxides in a one-pot process.

The key intermediate of a bioinspired iron catalyst for selective hydrocarbon oxidation based on hydrogen peroxide and an iron complex with a tetradentate aminopyridine ligand was trapped by EPR. On the basis of EPR and reactivity data this intermediate is tentatively proposed to be an oxoiron(V) complex.

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The asymmetric epoxidation of various electron-deficient olefins with H 2 O 2 in the presence of a novel family of chiral bioinspired bipyrrolidine-derived aminopyridine manganese(II) complexes [LM II (OTf) 2 ] is reported. High enantioselectivities (up to 99% ee) and epoxide selectivities (up to 100%), unprecedented for catalysts of this type, have been achieved; the catalysts perform up to 8500 catalytic turnovers. The presence of electron donors in the catalyst structure substantially enhances the enantioselectivity. Isotopic ( 18 O) labeling studies provide evidence of the formation of the oxomanganese(V) active species. Hammett analysis suggests that the enantioselective epoxidation is rate-limited by the transfer of an electron to the Mn V O intermediate, to form a short-lived acyclic (carbocationic) intermediate. In effect, the epoxide stereoconfiguration may be affected by the competition between the rotation around the C α −C β single bond and the epoxide ring collapse.

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