Investigation of new methods for the synthesis of C-C bonds is fundamental for the development of new organic drugs and materials. Aryl-, alkenyl- and alkynylboronic acids and their derivatives constitute attractive reagents towards this end, due to their stability, low toxicity and ease of handling. However, these compounds are only moderately nucleophilic. Consequently, the most popular C-C bond forming reactions of these boronic acids, such as the Suzuki-Miyaura, Heck, and Hayashi-Miyaura reactions, or additions to C=O and C=N bonds, require catalysis by transition metals. However, due to the toxicity and cost of transition metals, some new methods for C-C bond formation using aryl-, alkenyl- and alkynylboronic acids under transition-metal-free conditions are beginning to emerge. In this tutorial review, the recent synthetic advances in this field are highlighted and discussed.

Polyelectrolyte-surfactant mixtures and their interactions with fluid interfaces are an important research field due to their use in technological applications. Most of the existing knowledge on these systems is based on models in which the polyelectrolyte concentration is around 50 times lower than that used in commercial formulations. The present work marks a step to close the gap on the understanding of their behavior under more practically-relevant conditions. The adsorption of concentrated mixtures of poly(diallyldimethyl-ammonium) chloride and sodium N-lauroyl-N-methyltaurate at the water/vapor interface with a crude mixing protocol has been studied by different surface tension techniques, Brewster angle microscopy, neutron reflectometry, and several bulk characterization techniques. Kinetically-trapped aggregates formed during mixing influence the interfacial morphology of mixtures produced in the equilibrium one-phase region, yet fluctuations in the surface tension isotherm result depending on the tensiometric technique applied. At low bulk surfactant concentrations, the free surfactant concentration is very low, and the interfacial composition matches the trend of the bulk complexes, which is a behavior that has not been observed in studies on more dilute mixtures. Nevertheless, a transition to synergistic co-adsorption of complexes and free surfactant is observed at the higher bulk surfactant concentrations studied. This transition appears to be a special feature of these more concentrated mixtures, which deserves attention in future studies of systems with additional components.

The conjugate addition reaction of carbon nucleophiles to electron-deficient olefins is one of the most reliable methods for selective C-C bond formation. However, the conjugate addition to the vinylogous electron-deficient dienes has been much less developed, as there is considerably more difficulty in controlling the regioselectivity of the addition to these extended conjugate systems due to the presence of three electrophilic sites, as well as the stereoselectivity. Although still underdeveloped, new approaches to tackle these challenges are beginning to emerge. Both transition-metal-catalyzed and organocatalytic approaches are currently being developed to cope with the main selectivity issues of this type of process: regioselectivity (1,2-, 1,4-, and 1,6-addition) and stereoselectivity (asymmetric formation of the new C-C bonds). In this tutorial review, we have surveyed representative examples to get an overview of the recent advances obtained in the scope of the conjugate addition reaction of carbon nucleophiles to electron-deficient dienes.

Ring‐opening metathesis (ROM), when applied to the synthesis of bicyclic alkenes, is the basis of ring‐opening‐metathesis polymerisation (ROMP). This polymerisation reaction can be suppressed in the presence of a second open‐chain olefin thus combining the ROM with an intermolecular cross metathesis (CM). In conveniently substituted bicyclic derivatives a third metathetical reaction — ring closing metathesis (RCM) — can be achieved, giving new substituted bicyclic systems. In this account the results of these tandem metathetical reactions performed on oxa‐ and azabicyclic norbornenic derivatives are highlighted. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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The first examples of the direct arylation of benzo-fused 1,4-quinones by the dicationic Pd(II)-catalyzed addition of arylboronic acids are reported. The addition reaction is carried out under very mild conditions (dioxane-H(2)O, rt, open air atmosphere) and is tolerant of free OH groups. In addition, the reaction shows high regioselectivity when using nonsymmetrical quinones as starting materials.

The synthesis of di(hetero)arylamines by a transition-metal-free cross-coupling between nitrosoarenes and boronic acids is reported. The procedure is experimentally simple, fast, mild, and scalable and has a wide functional group tolerance, including carbonyls, nitro, halogens, free OH and NH groups. It also permits the synthesis of sterically hindered compounds.

No need for transition-metal catalysis in amination, amidation, nitration or nitrosation reactions with boron derivatives as reagents.