An operationally simple, one‐pot synthetic protocol for the formation of all‐carbon, highly substituted five‐ and six‐membered rings is described. In this two‐step procedure, an asymmetric allylic alkylation (AAA) of Morita–Baylis–Hillman (MBH) carbonates with allylmalononitrile, catalyzed by a chiral tertiary amine, is followed by a ring‐closing alkene metathesis (RCM) reaction. Products are obtained in high yields, and an excellent level of optical purity of some of the target compounds is achieved after just a single recrystallization.

The synthesis of batch-to-batch reproducible cyclodextrin (CD) derivatives often requires functionalization at specific positions of the CD skeleton. However, the regioselective preparation of this type of CD derivatives remains a challenge in synthetic chemistry. Thus, the present study aimed to prepare all positional regioisomers on the primary rim of homobifunctionalized diazido-α-CDs by selective substitution on the primary rim. Specifically, three positional regioisomers 6A,6B-, 6A,6C-, and 6A,6D-diazido-α-CDs were prepared via different intermediates (using sulfonylation with capping agents, bromination and tosylation). Furthermore, heterobifunctionalized 6A-azido-6X-mesitylenesulfonyl-α-CDs were also synthesized, and all regioisomers were successfully separated by HPLC. Moreover, the heterobifunctionalized α-CD regioisomers were isolated in gram-scale quantities, isomers AB and AC in the form of a pseudoenantiomeric mixture. The pseudoenantiomers AC/CA and AB/BA were resolved on an analytical scale by HPLC–MS at 10 °C. Thus, the presented synthetic and analytical methods for homo- and heterodisubstituted α-CDs are efficient and reproducible for the preparation of various pure regioisomeric CD derivatives. Accordingly, our findings indicate, (i) the versatility of selectively modified azido and mesitylene CD skeletons in preparing new types of α-CD derivatives and (ii) the potential of using resolved α-CD pseudoenantiomers in other research fields such as organocatalysis.

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Three cutting technologies, plasma, laser, and acetylene, were used to produce the same geometry of a hole with 33 cm diameter. The plates of the same steel St-37 (1.0038, ČSN 11375) with a thickness of 50 mm were used in all three cases and the aim of the work was to evaluate and compare microstructure changes of the cut surfaces. Longitudinal and transverse samples were taken from all cuts for subsequent analysis. Light and scanning electron microscopy of surface and below-surface areas were carried out at all samples. Hardness profiles were determined by micro-hardness and nano-hardness measurements. Based on these results, the depth of material that was influenced by cutting was established by image analysis of light micrographs, micro-hardness measurement and nano-hardness measurement. It was found out, that all three technologies influence significantly microstructure and surface hardness of cut steel. Acetylene cutting resulted in the deepest affected zone consisting of several layers with gradually changing microstructures based on various ferritic-carbidic morphologies.

The preparation of new organocatalysts for asymmetric syntheses has become a key stage of enantioselective catalysis. In particular, the development of new cyclodextrin (CD)-based organocatalysts allowed to perform enantioselective reactions in water and to recycle catalysts. However, only a limited number of organocatalytic moieties and functional groups have been attached to CD scaffolds so far. Cinchona alkaloids are commonly used to catalyze a wide range of enantioselective reactions. Thus, in this study, we report the preparation of new α- and β-CD derivatives monosubstituted with cinchona alkaloids (cinchonine, cinchonidine, quinine and quinidine) on the primary rim through a CuAAC click reaction. Subsequently, permethylated analogs of these cinchona alkaloid–CD derivatives also were synthesized and the catalytic activity of all derivatives was evaluated in several enantioselective reactions, specifically in the asymmetric allylic amination (AAA), which showed a promising enantiomeric excess of up to 75% ee. Furthermore, a new disubstituted α-CD catalyst was prepared as a pure AD regioisomer and also tested in the AAA. Our results indicate that (i) the cinchona alkaloid moiety can be successfully attached to CD scaffolds through a CuAAC reaction, (ii) the permethylated cinchona alkaloid–CD catalysts showed better results than the non-methylated CDs analogues in the AAA reaction, (iii) promising enantiomeric excesses are achieved, and (iv) the disubstituted CD derivatives performed similarly to monosubstituted CDs. Therefore, these new CD derivatives with cinchona alkaloids effectively catalyze asymmetric allylic aminations and have the potential to be successfully applied in other enantioselective reactions.