Chemo-, regio-, and stereoselective iron-catalysed hydroboration of alkenes and alkynes

The highly chemo-, regio-, and stereoselective synthesis of alkyl- and vinyl boronic esters with good functional group tolerance has been developed using in situ activation of a bench-stable iron(II) pre-catalyst and pinacolborane (16 examples, 45–95% yield, TOF up to 30000 mol h−1). The first iron-catalysed alkene hydrogermylation is also reported. </p

Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism

The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group in the para position or a cyano group in the ortho position. A range of other substituents gave no conversion of the aryl halide or led to the formation of side products. A broader scope was observed for the Grignard reagents, where a variety of alkyl- and arylmagnesium chlorides participated in the coupling. Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped. The cross-coupling reaction is therefore believed to proceed by an S(RN)1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor. Other mechanistic scenarios were excluded based on the substrate scope of the aryl halide

MECHANISTIC INVESTIGATIONS OF TRANSITION METAL CATALYZED REACTIONS

Transition metal catalyzed reactions have had a large impact on the human progress for the last century. Several extremely important areas, such as the agricultural industry and the plastic industry, have benefited from this development. The evolution of different transition metal catalysts has also been very important for the pharmaceutical industry. One vital factor when developing new and more effective catalysts is to obtain mechanistic insights. In this thesis, several different methods to investigate mechanisms for transition metal catalyzed reactions are presented. The factors controlling regioselectivity for a palladium catalyzed allylic alkylation has been studied. Pre-formed (η3-allyl)Pd complexes were used to minimize dynamic processes. In the study it was found that the regioselectivity depends mainly on steric interactions, rather than electronic effects. For complexes with less steric hindrance, the trans effect controlls the selectivity. Furthermore, the mechanism for a sulfinyl nucleophile, employed in the same type of reaction, has been studied and the mode of attack has been revealed. The importance of a fast palladium catalyzed Mislow-Braverman-Evans rearrangement to ensure that the correct product was formed, was also disclosed. The important Mizoroki-Heck reaction has been investigated in two different studies. The first study revealed the mechanistic pathway for a Pd(II) catalyzed domino Mizoroki-Heck-Suzuki diarylation reaction. The dependence of benzoquinone as the re-oxidant, in order to achieve the diarylation product, was explained by its ability to coordinate to the palladium moiety, thereby allowing access to a new low-energy pathway to the product. In the second study, a new and mild nickel catalyzed variant of the Mizoroki-Heck reaction was presented and the mechanistic pathway for the reaction was introduced. In addition to this, the reasons for several unsuccessful conditions and additives were uncovered. The development of new, environmentally more benign, catalysts for cross coupling reactions is important. Iron is one of the most promising metals for this purpose, but the mechanistic knowledge of this reaction is still not comprehensive. In this thesis, several mechanistic and computational studies reveal new insights into this reaction, paving the way to develop new and more effective catalysts and conditions for the reaction

Do you use PFAS in your business? The PFAS guide will help you find out

Slides that were presented as part of the ZeroPM webinar series. The recording can be found on the youtube channe

En problemlösningsapplikation för Sveriges schackförbund

The purpose of this project was to investigate whether it was possible to develop a type of application, where users would solve chess problems. The main goal of the project was that there would exist an functional application after the study has ended with which users could solve chess problems on a computer. One subgoal of the project was to create corresponding application for mobile phones. The study was limited to require users to have at least Internet Explorer 9 +. For other browsers, there were no corresponding limitations. The study did not investigated which programming language that really would be best suited for this kind of project. The project was developed in JavaScript and HTML. After completing the study, it was found that such an application could be created. The application has been tested on standard computer with different screen resolutions, and on mobile phones which use Android. On these, it was found that there were no problems with the appearance or functionality. Keywords: JavaScript, HTML, chess, problem solvin

Computational Insights into Palladium-Mediated Allylic Substitution Reactions

Allyl palladium complexes have a rich chemistry. Many aspects of their structure and reactivity have been studied computationally. This chapter gives an overview of the history in this field, from structural studies and the effect of ligands and substituents, to the rich reactivity of the title complexes. The latter includes complex formation, reactions with nucleophiles and electrophiles, and dynamic equilibria. An important focus area has been the TsujiIt1;ndash;Trost reaction, in particular asymmetric versions thereof. A brief overview of computational methods, aimed at modeling novices, can be found in the introduction

Ionization of ammonium dinitramide: decomposition pathways and ionization products

The decomposition pathways of ionized ammonium dinitramide (ADN) have been analyzed using the B3LYP and the M06-2X density functional theory methods, coupled cluster theory and the composite CBS-QB3 method. Ionization and subsequent decomposition of the major decomposition products have also been studied. The ADN(+) ion dissociates into the stable DN radical and NH4+ with a dissociation enthalpy of 50 kJ/mol. The subsequently formed DN+ ion has an activation enthalpy of 102 kJ/mol for decomposition into N2O, O-2 and NO+. A competing pathway for ionization and decomposition of ADN involves the HDN+ ion, which dissociates into NO2+ and HNNO2 with a barrier of only 17 kJ/mol. The ionization product HNNO2+ is stable toward further decomposition, and the barrier for isomerization to HONNO+ is 167 kJ/mol. The computed adibatic ionization potentials of ADN, HDN, DN and HNNO2 are 9.4, 11.5, 10.2 and 10.9 eV, respectively. The results of the study have implications for the future use of ADN in propellants for electromagnetic space propulsion.</p