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Versatile, two-step syntheses of dihydrodibenzo[c,e]azepines, carbazole derivatives, and other alkaloid-type drug-like scaffolds by in situ generated azomethine ylide-induced intramolecular electrocyclization reaction from commercially available materials are presented. The reaction mechanisms of transition-metal-free carbon–carbon bond formation and the role of the kinetic control, resulting in the good regioselectivity, were confirmed by theoretical calculations.

Novel poly(dithiophosphate)s (PDTPs) were successfully synthesized under mild conditions without any additive in the presence of THF or toluene diluents at 60 °C by a direct, catalyst-free reaction between the abundant phosphorus pentasulfide (P4S10) and glycols such as ethylene glycol (EG), 1,6-hexanediol (HD) and poly(ethylene glycol) (PEG). GPC, FTIR, 1H and 31P NMR analyses proved the formation of macromolecules with dithiophosphate coupling groups having P=S and P-SH pendant functionalities. Surprisingly, the ring-opening of THF by the P-SH group and its pendant incorporation as a branching point occur during polymerization. This process is absent with toluene, providing conditions to obtain linear chains. 31P NMR measurements indicate long-time partial hydrolysis and esterification, resulting in the formation of a thiophosphoric acid moiety and branching points. Copolymerization, i.e., using mixtures of EG or HD with PEG, results in polymers with broadly varying viscoelastic properties. TGA shows the lower thermal stability of PDTPs than that of PEG due to the relatively low thermal stability of the P-O-C moieties. The low Tgs of these polymers, from −4 to −50 °C, and a lack of PEG crystallites were found by DSC. This polymerization process and the resulting novel PDTPs enable various new routes for polymer synthesis and application possibilities.

A general, scalable two-step regio- and diastereoselective method has been described for the synthesis of versatile alkaloid-type azetidines from simple building blocks with excellent overall yields. In the kinetically controlled reaction, only the formation of the strained four-membered ring can be achieved instead of the thermodynamically favorable five-membered rings under appropriate conditions. Remarkable functional group tolerance has also been demonstrated. In this paper, we give a new scope of Baldwin's rules by density functional theory (DFT) calculations with an explicit solvent model, confirming the proposed reaction mechanisms and the role of kinetic controls in the stereochemical outcome of the reported transition-metal-free carbon-carbon bond formation reactions.

Copolymers containing hydroxyl (i.e. vinyl alcohol, VA) or fluorine functionalities are synthetic macromolecules having prominent biomedical applications. The concentration of hydroxyl groups along the polymer chain controls the polymer polarity. Moreover, the introduction of perfluorinated organic moieties via the OH functionalities may lead to macromolecules having potential magnetic resonance imaging (MRI) active properties. The ring-opening metathesis polymerization (ROMP) reaction using well-defined ruthenium-catalyzed systems is one of the most promising synthetic tools to fabricate such polymers. Co-polymerization of norbornene grafted pyridino-18-crown-6 ether (7) with fluorine-functionalized norbornenes (10 and 11) results in polymers bearing host molecular moieties. It has been demonstrated that the complexation of these host copolymers with biogenic amines including dopamine hydrochloride (12) and L-alanyl-L-lysine dipeptide hydrochloride (13) is straightforward. Based on the 1H NMR investigation of the 7 and 12 complexation, an equilibrium constant of log K = 4.3 ± 0.6 could be calculated. The in situ1H NMR investigations have revealed that the complex formation of 13 with monomer 7 and perfluorinated copolymer cp-7-10 takes place via both the lysine –NH3+ and the alanine –NH3+ moieties. However, in the case of homopolymer poly-7, the lysine–NH3+ group coordination was observed exclusively. According to theoretical calculations, molecular switching of the crown ether structure of both the 7 monomer and its cp-7-10 copolymer were observed from 90 degrees bent to planar structure upon –NH3+ ion coordination.

Cross-metathesis (CM) of conjugated polyenes, such as 1,6-diphenyl-1,3,5-hexatriene ( 1 ) and α-eleostearic acid methyl ester ( 2 ) with several olefins, including 1-hexene, dimethyl maleate and cis -stilbene as model compounds has been carried out using (1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)-dichloro( o -isopropoxyphenylmethylene)ruthenium (Hoveyda-Grubbs 2nd generation, HG2 ) catalyst. The feasibility of these reactions is demonstrated by the observed high conversions and reasonable yields. Thus, regardless of the relatively low electron density, =CH–CH= conjugated units of molecules, including compound 2 as a sustainable, non-foodstuff source, can be utilized as building blocks for the synthesis of various value-added chemicals via olefin metathesis. DFT-studies and the product spectrum of the self-metathesis of 1,6-diphenyl-1,3,5-hexatriene suggest that a Ru η 1 -allylidene complex is the active species in the reaction.

The present study reports regio- and highly diastereoselective preparative methods for the synthesis of versatile alkaloid-type compounds from oxiranylmethyl tetrahydroisoquinolines. 2,5-Methanobenzo[ c]azepines or azetidine-fused heterocycles were synthesized in tandem reactions depending on the absence or presence of a BF3 co-reagent. A high functional group tolerance has also been demonstrated. DFT calculations with an explicit solvent model confirmed the proposed reaction mechanisms and the role of kinetic controls on the stereochemical outcome of the reported new methods.

New methods for efficient preparation of optically active compounds developed recently are reported. Combination of selective organometallic, organocatalytic, phase transfer catalytic and catalytic hydrogenation reactions provided numerous new optically active members of the families of atropisomeric 1-phenylpyrrole derivatives, 4-aminobutan-1-ol and 3,4-disubstituted pyrrolidine derivatives and optically active α- and β-aminophosphonic acids. The products can be used as valuable new chiral ligands or organocatalysts and can serve as building blocks of practically important biologically active compounds.

Some N- and O-protected hydroxyazetidine derivatives were hydrogenated to the corresponding amines or aminoalcohols over a Pd/C catalyst, in different solvents (methanol, dichloromethane, tetrahydrofuran), at 30–60 °C and 1–10 bar. These amino compounds, formed during hydrogenolytic ring opening and/or deprotecting reactions, are potential starting materials for preparing optically active, practically important pyrrolidine derivatives.

A novel, superbase induced diastereoselective transformation of benzylamino groups containing oxiranes has provided a series of trans-1,2,3-trisubstituted azetidines in good yields. The reaction of the corresponding optically active cis-2,3-disubstituted oxirane yielded the azetidine derivative as a single enantiomer. The structures of the new azetidines were confirmed by NMR spectroscopic methods and, in one case, by single crystal diffraction measurements.

An efficient method for the palladium mediated hydrogenation of an optically active, N-protected aminooxetane derivative has been developed. Using appropriate solvents, in a one-step reaction, a chiral 1,4-aminoalcohol derivative [(2S,3R)-4-amino-3-benzoyloxy-2-benzylbutan-1-ol] was formed over a Pd/C catalyst, during hydrogenolytic ring opening and debenzylation reactions.

An efficient method for the palladium mediated hydrogenation of an optically active, O -protected hydroxyoxetane derivative has been developed. Using appropriate solvents, in a one-step reaction, optically active 1,4-diol was formed over a Pd/C catalyst, during hydrogenolytic ring opening and detritylation reactions.

A variety of dihydrofuran (XIV), tetrahydrofuran (IX), dioxole (III), (VII) and pyrrolidine derivatives (XII) is prepared starting from triol (I) or its partially protected analogues.

Not all amide bonds are created equally. The purpose of the present paper is the reinterpretation of the amide group by means of two concepts: amidicity and carbonylicity. These concepts are meant to provide a new viewpoint in defining the stability and reactivity of amides. With the help of simple quantum-chemical calculations, practicing chemists can easily predict the outcome of a desired process. The main benefit of the concepts is their simplicity. They provide intuitive, but quasi-thermodynamic data, making them a practical rule of thumb for routine use. In the current paper we demonstrate the performance of our methods to describe the chemical character of an amide bond strength and the way of its activation methods. Examples include transamidation, acyl transfer and amide reductions. Also, the method is highly capable for simple interpretation of mechanisms for biological processes, such as protein splicing and drug mechanisms. Finally, we demonstrate how these methods can provide information about photo-activation of amides, through the examples of two caged neurotransmitter derivatives.