decades. The ability to rearrange carbon-carbon double bonds has provided great utility in all aspects of organic chemistry. Cossy et al. report a simple synthesis to form substituted five and six membered lactones from the cross metathesis of an allylic or homoallylic alcohol and acrylic acid using a ruthenium based metathesis catalyst. Lactones are good synthetic starting points for many natural products and are prevalent structures in biology therefore they are widely utilized in pharmaceuticals. Carbonylation One of the most studied and commercially important transition metal catalyzed reactions is alkene hydroformylation. This type of catalysis allows for the functionalization of simple alkenes into aldehydes and gives a remarkably useful handle to generate other functional groups. This transformation can be carried out using a cobalt or rhodium catalyst in a hydrogen/carbon monoxide atmosphere and consists of four stages: metal insertion, migratory insertion, heterolytic cleavage, and ligand exchange. Breit et al. generated extended alkane functionality by hydroformylation, olefination, and then hydrogenation. Orthogonal tandem catalysis Orthogonal tandem catalysis is a "one-pot reaction in which sequential catalytic processes occur through two or more functionally distinct, and preferably non-interfering, catalytic cycles". This technique has been deployed in tandem alkane-dehydrogenation-olefin-metathesis catalysis Photoprotection tandem catalysis Recently, tandem catalysis mechanism is proposed for significant photoprotection of dye, pigment, and polymers in paints and coatings when cerium carbonate is used together with photoactive metal oxide like titanium oxide. See also Chain shuttling polymerization References Catalysis