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V uvodnem delu diplomskega dela so predstavljene Diels–Alderjeve reakcije, njihova stereokemija in regioselektivnost. Opisane so tudi značilnosti sodelujočih dienov in dienofilov. Večji poudarek je namenjen 2H-piran-2-onom, ki predstavljajo zanimive diene za [4+2] cikloadicije. Na kratko so predstavljene tudi teoretične študije mehanizma Diels–Alderjevih reakcij. Večji del teoretičnega uvoda pokriva predstavitev organokatalize, klasifikacija le-te na kovalentno in nekovalentno katalizo in predstavitev predstavnikov posamezne organokatalize. Narejen je tudi manjši oris uporabe predstavljene katalize pri Diels–Alderjevih reakcijah, kjer 2H-piran-2-oni igrajo vlogo diena. Eksperimentalni del se navezuje na pripravo substituiranih 3-benzoilamino-2H-piran-2-onov, odščito aminske skupine pod kislimi pogoji ter uvedbo nove zaščitne skupine s pomočjo ustreznega kislinskega klorida. Izvedeni sta bili tudi Diels–Alderjevi reakciji z izbranim derivatom 2H-piran-2-ona in maleinanhidridom pod refluksom ter z obsevanjem z mikrovalovi. The Diploma work presents Diels–Alder reactions, their stereochemistry and regioselectivity. It covers the properties of typically used dienes and dienophiles. 2H-Pyran-2-ones are reviewed in detail, as they present interesting dienes in [4+2] cycloadditions. The theoretical studies of Diels–Alder reaction mechanism are also briefly addressed. A large part of the theoretical introduction is comprised of a review of organocatalysis. Covalent and non-covalent catalysis and the representatives of organocatalytic methods are introduced. A brief description of organocatalytic Diels–Alder reactions of 2H-pyran-2-ones is presented. In the experimental work, the synthesis of 3-benzoylamino-2H-pyran-2-ones, selective deprotection of the 3-amino group under acid conditions and an addition of a new protective group with a corresponding acyl chloride is presented. It is followed by two Diels–Alder reactions using a derivate of 2H-pyran-2-one and maleic anhydride. The described [4+2] cycloadditions were investigated under reflux and microwave irradiation.

In the last years the use of chalcogen bonding—the noncovalent interaction involving electrophilic chalcogen centers—in noncovalent organocatalysis has received increased interest, particularly regarding the use of intermolecular Lewis acids. Herein, we present the first use of tellurium‐based catalysts for the activation of a carbonyl compound (and only the second such activation by chalcogen bonding in general). As benchmark reaction, the Michael‐type addition between trans‐crotonophenone and 1‐methylindole (and its derivatives) was investigated in the presence of various catalyst candidates. Whereas non‐chalcogen‐bonding reference compounds were inactive, strong rate accelerations of up to 1000 could be achieved by bidentate triazolium‐based chalcogen bond donors, with product yields of >90 % within 2 h of reaction time. Organotellurium derivatives were markedly more active than their selenium and sulphur analogues and non‐coordinating counterions like BArF 4 provide the strongest dicationic catalysts., Make it active! Tellurium‐based dicationic chalcogen bonding organocatalysts have been used to activate a carbonyl compound in the Michael addition reaction between indole derivatives and trans‐crotonophenone. Up to 1000‐fold rate accelerations were observed compared to the corresponding iodinated halogen bond donor. Several comparison experiments were performed to rule out other modes of activation than chalcogen bonding.

International audience; The ubiquitous presence of spirooxindole architectures with several functionalities and stereogenic centers in bioactive molecules has been appealing for the development of novel methodologies seeking their preparation in high yields and selectivities. Expansion and refinement in the field of asymmetric organocatalysis have made possible the development of straightforward strategies that address these two requisites. In this review, we illustrate the current state-of-the-art in the field of spirooxindole synthesis through the use of non-covalent organocatalysis. We aim to provide a concise overview of very recent methods that allow to the isolation of unique, densely and diversified spirocyclic oxindole derivatives with high structural diversity via the use of cascade, tandem and domino processes.

Organocatalysis, that is the use of small organic molecules to catalyze organic transformations, has been included among the most successful concepts in asymmetric catalysis, and it has been used for the enantioselective construction of C–C, C–N, C–O, C–S, C–P and C–halide bonds. Since the seminal works in early 2000, the scientific community has been paying an ever-growing attention to the use of organocatalysts for the synthesis, with high yields and remarkable stereoselectivities, of optically active fine chemicals of interest for the pharmaceutical industry. A brief overview is here presented about the two main classes of substrate activation by the catalyst: covalent organocatalysis and non-covalent organocatalysis, with a more stringent focus on some recent outcomes in the field of the latter and of hydrogen bond-based catalysis. Finally, some successful examples of heterogenization of organocatalysts are also discussed, in the view of a potential industrial exploitation.