Cobalt-Catalyzed Stereoretentive Hydrogen Isotope Exchange of C(sp)-H Bonds.

Cobalt dialkyl complexes bearing -diimine ligands proved to be active precatalysts for the nondirected, C(sp)-H selective hydrogen isotope exchange (HIE) of alkylarenes using D gas as the deuterium source. Alkylarenes with a variety of substitution patterns and heteroatom substituents on the arene ring were successfully labeled, enabling high levels of incorporation into primary, secondary, and tertiary benzylic C(sp)-H bonds. In some cases, the HIE proceeded with high diastereoselectivity and application of the cobalt-catalyzed method to enantioenriched substrates with benzylic stereocenters provided enantioretentive hydrogen isotope exchange at tertiary carbons.

Benzyltriboronates: Building Blocks for Diastereoselective Carbon-Carbon Bond Formation.

A highly diastereoselective carbon-carbon bond-forming reaction involving the tandem coupling of benzyltriboronates, enoates, and alkyl halides is described. This method was enabled by the discovery of α-diimine nickel catalysts that promote the chemoselective triborylation of benzylic C(sp)-H bonds using BPin (Pin = pinacolate). The C-H functionalization method is effective with methylarenes and for the diborylation of secondary benzylic C-H bonds, providing direct access to polyboron building blocks from readily available hydrocarbons.

Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp(3))-H Bonds.

Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp(3))-H borylation of a range of substituted alkyl arenes using B2Pin2 (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp(3))-H bonds.

Premature ejaculation: a clinical update.

Premature ejaculation (PE) is ejaculation occurring without control, on or shortly after vaginal penetration and before the subject wishes it, causing marked distress or interpersonal difficulties. PE is the most common male sexual complaint. Primary (lifelong) PE has a physiological basis.

Erectile dysfunction predicts generalised cardiovascular disease: evidence from a case-control study.

Aims: To determine whether idiopathic erectile dysfunction, in the absence of overt cardiovascular disease or cardiovascular risk factors, is associated with vascular or autonomic dysfunction.

Methods: We studied 49 men with ED (without known cardiovascular risk factors or disease) and 50 age-matched controls, aged 40-70 years. Macrovascular endothelial function was examined by brachial artery ultrasonography and microvascular function by venous occlusion plethysmography.