Alkene syn- and anti-oxyamination with malonoyl peroxides

Malonoyl peroxide [6] is an effective reagent for the syn- or anti-oxyamination of alkenes. Reaction of [6] and an alkene in the presence of O-tert-butyl-N-tosylcarbamate (R3 = CO2tBu) leads to the anti-oxyaminated product in up to 99% yield. Use of O-methyl-N-tosyl carbamate (R3 = CO2Me) as the nitrogen nucleophile followed by treatment of the product with trifluoroacetic acid leads to the syn-oxyaminated product in up to 77% yield. Mechanisms consistent with the observed selectivities are proposed

The influence of Mn on the tensile properties of SSM-HPDC A1-Cu-Mg-Ag alloy A201

Synopsis: A201 aluminium alloy is a high strength casting alloy with a nominal composition of Al-4.6Cu-0.3Mg-0.6Ag. It is strengthened by the Ω(Al2Cu) phase and the θ’(Al2Cu) phase during heat treatment. Further strengthening of this alloy system can be obtained through the addition of transition elements, but care must be taken as other elements might have adverse effects on the mechanical properties. The objective of this study is to determine the influence of Mn on the tensile properties of rheo-processed Al-Cu-Mg-Ag alloy A201. ThermoCalc software was used to predict the different phases that can be expected in the alloys, and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) was used to investigate the actual phases that formed. The influence of these phases on tensile properties is quantified. SEM and ThermoCalc revealed that there is an increased amount of the Al20Cu2Mn3 with increasing Mn. The tensile properties showed that high amounts of Mn do have adverse effects on the tensile properties of alloy A201, especially the ductility

Alkene oxyamination using malonoyl peroxides : preparation of pyrrolidines and isoxazolidines

Treatment of homoallylic N-tosyl amines or allylic N-tosyl hydroxylamines with 1.5 equiv of a malonoyl peroxide provides a stereoselective method to access functionalized pyrrolidines and isoxazolidines. This metal free alkene oxyamination proceeds in 50-85% yield and up to 13:1 trans-selectivity. In addition, the relative stereochemistry of the oxygen and nitrogen substituents can be inverted through an oxidation/reduction sequence or inverting the stereochemistry of the starting alkene. Mechanistic investigations show a higher reactivity for hydroxyl nucleophiles over sulfonamide nucleophiles revealing a preference for dioxygenation over oxyamination

Staff Perspectives of Service User Involvement on Two Clinical Psychology Training Courses

This study investigated both negative and positive staff perspectives of service user involvement on two clinical psychology training courses as part of an ongoing process of service evaluation. Ten clinical psychology staff from two training courses were interviewed over the telephone by a current trainee clinical psychologist using a semi-structured interview method. Data were coded into textual units of meaning and then analysed using content analysis. The categories most cited by participants regarding the positives of service user involvement were that it 'develops trainees' learning' and 'challenges power differences'. For opportunities of service user involvement to provide benefits to the training courses, most participants cited 'meaningful versus tokenistic involvement', followed by 'strategic involvement'. Regarding negatives and barriers, those most cited were 'differences of opinion or agendas' and 'lack of resources'. Whilst the findings suggested that the service user involvement initiatives on both courses have been well received, research is needed into how service users also experience the process. Interventions that facilitate staff reflection and processing of multiple perspectives was also recommended, particularly with regards to negative experiences of service user involvement

Equivalences between localisations of categories provided by replacements

We give a characterisation of functors whose induced functor on the level of localisations is an equivalence and where the isomorphism inverse is induced by some kind of replacements such as projective resolutions or cofibrant replacements

Mapping the Archaeology of Somaliland: Religion, Art, Script, Time, Urbanism, Trade and Empire

FdA – Publicaties zonder aanstelling Universiteit LeidenHeritage of Indigenous People