Synthetic applications of the catalytic asymmetric 1,4-addition

De organische chemie, het vakgebied waarbinnen het onderzoek beschreven in dit proefschrift is uitgevoerd, kan worden gedefinieerd als de chemie van koolstofbevattende verbindingen. Deze definitie kan op het eerste gezicht nogal beperkt lijken, maar men moet zich realiseren dat het overgrote deel van alle stoffen die op aarde gevonden worden onder deze definitie vallen. ... Zie: Samenvattin

Unexpected enhancement of enantioselectivity in copper(II) catalyzed conjugate addition of diethylzinc to cyclic enones with novel TADDOL phosphorus amidite ligands

The copper(II) catalyzed enantioselective 1,4-addition reactions of diethylzinc to cyclic enones in the presence of novel phosphorus amidite ligands, easily prepared from α,α,α',α'-tetraphenyl-2,2'-dimethyl-1,3-dioxolane-4,5-dimethanol (TADDOL) derivatives, resulted in e.e.s up to 71% for cyclohexenone and up to 62% for cyclopentenone. A remarkable enhancement of enantioselectivity was observed upon the addition of powdered molecular sieves to the reaction mixture

Atomic spectrometry update: Review of advances in the analysis of metals, chemicals and materials

There has been a large increase in the number of papers published that are relevant to this review over this review period. The growth in popularity of LIBS is rapid, with applications being published for most sample types. This is undoubtedly because of its capability to analyse in situ on a production line (hence saving time and money) and its minimally destructive nature meaning that both forensic and cultural heritage samples may be analysed. It also has a standoff analysis capability meaning that hazardous materials, e.g. explosives or nuclear materials, may be analysed from a safe distance. The use of mathematical algorithms in conjunction with LIBS to enable improved accuracy has proved a popular area of research. This is especially true for ferrous and non-ferrous samples. Similarly, chemometric techniques have been used with LIBS to aid in the sorting of polymers and other materials. An increase in the number of papers in the subject area of alternative fuels was noted. This was at the expense of papers describing methods for the analysis of crude oils. For nanomaterials, previous years have seen a huge number of single particle and field flow fractionation characterisations. Although several such papers are still being published, the focus seems to be switching to applications of the nanoparticles and the mechanistic aspects of how they retain or bind with other analytes. This is the latest review covering the topic of advances in the analysis of metals, chemicals and materials. It follows on from last year's review1-6 and is part of the Atomic Spectrometry Updates series

A Catalytic Route to Acyclic Chiral Building Blocks: Applications of the Catalytic Asymmetric Conjugate Addition of Organozinc Reagents to Cyclic Enones

Through the Cu-phosphoramidite catalyzed asymmetric conjugate addition a number of chiral cyclic enones are available with high ee. Herein we report the sequential conjugate addition to these enones as a route towards multisubstituted chiral cyclic ketones. A subsequent Baeyer-Villiger oxidation followed by ring-opening results in various linear synthons containing multiple stereocenters. This procedure represents a short, catalytic, and highly enantioselective route to a variety of acyclic chiral building blocks.