Professor Vollhardt and his coworkers are interested in the application of transition metals to organic synthesis. The areas under investigation range from the assembly of novel oligometallic arrays to the use of cobalt, palladium, and nickel in the construction of complex organic molecules.
For example, his group has developed ways to attach cyclopentadienylmetal units repeatedly to other p-ligands, such as cyclopentadienyl itself. In this way, a number of potentially catalytic and conducting oligocyclopentadienylmetals with remarkable properties have become available for further exploration.
A second effort underway is directed at further exploring the scope of the cobalt-mediated [2+2+2]cycloaddition of alkynes to other unsaturated substrates, a reaction pioneered by the Vollhardt group. Recent work has focused on "tagging" heteroaromatic systems, such as the indole alkaloids, resulting in a total synthesis of strychnine and a novel approach to morphinoids.
A third problem is concerned with the synthesis of molecules of theoretical importance, in particular highly strained hydrocarbons and molecules with electronically destabilizing features. These include the phenylenes, a class of novel benzenoids in which benzene and cyclobutadiene are fused in an alternating manner. Their properties are remarkable, in particular with respect to cyclohexatrienic reactivity of the benzene nuclei and their potential to behave as organic magnets and conductors.