Anti-Bredt alkenes, bicyclic molecules that contain a bridgehead double bond, were for many years regarded as chemical curiosities. The type 2 intramolecular Diels-Alder (IMDA) reaction provides a one-step entry into this fascinating class of molecules. The reaction has made available numerous anti-Bredt alkenes for structural and chemical studies. X-ray crystallography has revealed the magnitu...

Following the pioneering Ziegler addition of nucleophiles to nonactivated unsaturated carbon–carbon bonds, the controlled carbometallation reaction has emerged. Since then, reactions that result in the addition of a carbon–metal bond of an organometallic across a carbon–carbon unsaturated system, leading to a new organometallic in which the newly formed carbon–metal bond can be used for further...

We determined the quantity and chemical composition of cuticular hydrocarbons of different strains, sex and age of buffalo flies, Haematobia exigua. The quantity of cuticular hydrocarbons increased from less than 1 μg/fly for newly-emerged flies to over 11 μg/fly in 13 d-old flies. The hydrocarbon chain length varied from C21 to C29, with unbranched alkanes and monounsaturated alkenes the major...

Heterogeneous semiconductor photoredox catalysis (SCPC), particularly with TiO2, is evolving to provide radically new synthetic applications. In this review we describe how photoactivated SCPCs can either (i) interact with a precursor that donates an electron to the semiconductor thus generating a radical cation; or (ii) interact with an acceptor precursor that picks up an electron with product...

Transition metal–catalyzed asymmetric hydrofunctionalization of alkenes provides straightforward approaches to access optically active organic compounds. Rhodium compounds ligated by chiral phosphine ligands are the most frequently used catalysts for enantioselective hydrogenation reactions unsaturated molecules containing C=C and C=N bonds. However, rapid development cobalt catalysis over past...

It is shown that model oxides grown on metallic substrates catalyze propylene metathesis to form ethylene and butene with an activity that mimics that of supported catalysts for reaction below ∼650 K. Another reaction regime is found for olefin metathesis above ∼650 K, where the reaction proceeds with a much higher activation energy of ∼60 kcal/mol. Unfortunately, alkenes do not react to any de...

Hydrocarbons in air were determined at pioneering European service stations equipped with vapour recovery systems. Vapour recovery was found capable of eliminating 99% of exposure during refuelling and greater than 95% of emissions to air. Vapour recovery is now being rapidly introduced at Swedish service stations as a result of demands concerning environmental and health hazards. The analytica...

In plants, pollinator adaptation is considered to be a major driving force for floral diversification and speciation. However, the genetic basis of pollinator adaptation is poorly understood. The orchid genus Ophrys mimics its pollinators' mating signals and is pollinated by male insects during mating attempts. In many species of this genus, chemical mimicry of the pollinators' pheromones, espe...

A general method for the hydro-alkyl addition to the nonactivated C=C double bond of alkenes using alkyl chloroformates (primary, secondary), 12, and di-tert-butylpyrocarbonate, 52, mediated by ethylaluminum sesquichloride (Et(3)Al(2)Cl(3)) has been developed. Reaction of 12 and 52, respectively, with Et(3)Al(2)Cl(3) gives an alkyl cation which is added to the alkene; hydride transfer to the ad...