POLYCYCLIC AROMATIC HYDROCARBON BOWLS,BASKETS, BALLS,AND TUBES: CHALLENGING TARGETS FOR CHEMICAL SYNTHESIS

The number of unique chemical substances registered by the Chemical Abstracts Service passed the 50 million mark in September 2009. The vast majority of these substances were brought into existence by chemical synthesis, a human activity that has grown immensely powerful and continues to advance at an ever-accelerating pace. It would not be unreasonable for the average layman to assume that chemists must now be able to synthesize everything imaginable; however, that Utopian level of success has not been achieved. Some molecular targets remain beyond the reach of chemical synthesis by present day methods. When fullerenes and carbon nanotubes were discovered near the end of the 20th century, for example, scientists quickly recognized that chemical methods to synthesize such large, curved, polycyclic aromatic structures simply did not exist. Since that time, progress has been made on the development of methods for this purpose, and the present article recounts some of the advances along those lines that have been made in the author’s laboratory.