Reaction Pathways and Redox States in α-Selective Cobalt-Catalyzed Hydroborations of Alkynes.

Cobalt(II) alkyl complexes supported by a monoanionic NNN pincer ligand are pre-catalysts for the regioselective hydroboration of terminal alkynes, yielding the Markovnikov products with α:β-(E) ratios of up to 97:3. A cobalt(II) hydride and a cobalt(II) vinyl complex appear to determine the main reaction pathway. In a background reaction the highly reactive hydrido species specifically converts to a coordinatively unsaturated cobalt(I) complex which was found to re-enter the main catalytic cycle.

Tackling N-Alkyl Imines with 3d Metal Catalysis: Highly Enantioselective Iron-Catalyzed Synthesis of α-Chiral Amines.

A readily activated iron alkyl precatalyst effectively catalyzes the highly enantioselective hydroboration of N-alkyl imines. Employing a chiral bis(oxazolinylmethylidene)isoindoline pincer ligand, the asymmetric reduction of various acyclic N-alkyl imines provided the corresponding α-chiral amines in excellent yields and with up to >99 % ee. The applicability of this base metal catalytic system was further demonstrated with the synthesis of the pharmaceuticals Fendiline and Tecalcet.

Borohydride intermediates pave the way for magnesium-catalysed enantioselective ketone reduction.

A magnesium precatalyst for the highly enantioselective hydro-boration of C[double bond, length as m-dash]O bonds is reported. The mechanistic basis of the unprecedented selectivity of this transformation has been investi-gated experimentally by isolation of catalytic intermediates and theoretically by DFT calculations. The facile formation of a magnesium borohydride species is critical in overcoming competing pathways in the selectivity-determining insertion step.

[Impairments of cognitive control in patients with somatoform disorders and their treatment].

Aim: To study impairments of cognitive control in patients with somatoform disorders (SD) and to evaluate the efficacy of recognan in the treatment of this pathology.

Material And Methods: Forty-six patients with SD, aged from 18 to 45 years, were studied. A clinical history, neurological examination, and assessment of autonomic disorders were collected from all patients.

Melt flow of biopolymer through the cavities of an extruder die: Mathematical modelling.

This is an analytical solution of the two-dimensional non-isothermal mathematical model describing the change in the velocity profile of a cylindrical extrusion die. This solution is based on the following assumptions. The two-dimensional melt flow is asymmetric.