The neurobiology of the male sexual refractory period.

Despite having been recognized for many years, the mechanisms governing the male sexual refractory period (post-ejaculatory refractory period, post-ejaculatory interval) remain poorly understood. This review examines the brain and spinal areas putatively involved in this phenomenon to draw a coherent picture from the available data. It is hoped that this will reveal where further research will offer the potential for crucial insights on this topic.

Platinum-Catalyzed α,β-Unsaturated Carbene Formation in the Formal Syntheses of Frondosin B and Liphagal.

Formal syntheses of tetracyclic terpenoids frondosin B and liphagal are described. Both synthetic routes rely on the use of platinum-catalyzed α,β-unsaturated carbene formation for the key C-C bond forming transformations. The successful route toward frondosin B utilizes a formal (4 + 3) cycloaddition, while the liphagal synthesis features the vinylogous addition of an enol nucleophile as a key step.

An examination of the scope and stereochemistry of the Ireland-Claisen rearrangement of boron ketene acetals.

The Ireland-Claisen rearrangement of boron ketene acetals is described. The boron ketene acetal intermediates are formed through a soft enolization that obviates the use of strong bases and the intermediacy of alkali metal enolates. Yields and diastereoselectivities of these rearrangements are very sensitive to the choice of boron reagent, even among those that have been shown to effect quantitative formation of boron ketene acetals from esters.

A cope rearrangement-based route to hexahydroazulenes.

2-exo-Vinyl-7-alkylidenenorbornanes, readily prepared from fulvene Diels-Alder adducts, undergo smooth Cope rearrangement at elevated temperatures to produce hexahydroazulene derivatives.