No abstract

Asymmetric hydrogenations are increasingly being used to introduce stereogenic centres into products used in the life sciences industries. There are a number of potential pitfalls when moving from a laboratory reaction to a manufacturing process, not least of which is safety. Time-to-market pressure leads to short development times, which in the past could be a large barrier for the implementation of catalytic steps; now there are new ways to minimise this problem. The potential problems associated with impurities and other methods that can shut down the hydrogenation reactions are highlighted in this critical review (353 references).

Noteworthy developments of the Peterson olefination reaction are reviewed. Evidence for both concerted and stepwise mechanisms for the Peterson olefination reaction is presented. The strong affinity of the oxygen anion for the silyl moiety is emphasised when the Peterson olefination reaction takes preference over both the Julia and Wittig reactions in the presence of S- and P-stabilised silyl carbanions. Cerium-mediated Peterson methylenation reactions are discussed.

No abstract

We demonstrate essentially complete exfoliation of graphene aggregates in water at concentrations up to 5% by weight (166-fold greater than previous high concentration report) using recently developed triblock copolymers and copolymeric nanolatexes based on a reactive ionic liquid acrylate surfactant. We demonstrate that the visible absorption coefficient in aqueous dispersion, 48.9 ± 1.3 cm(2)/mg at 500 nm, is about twice that currently accepted, and we show that this value is a greatest lower bound to extant macroscopic single sheet optical studies of graphene when one considers both fine structure constant and excitonic mechanisms of visible absorption. We also show that dilute and concentrated graphene dispersions are rheo-optical fluids that exhibit an isotropic to nematic transition upon application of a shear field, and we demonstrate stimuli-responsive phase transfer.

No abstract

No abstract

Aspartame (1), saccharin (2), and acesulfam‐K (3) are sweeteners that are in everyday use. The market for these nonnutritive sweeteners is therefore large. The properties and large‐scale syntheses of these commercial products and others that are in advanced stages of development are reviewed.