The fifth element in drug design: Boron in medicinal chemistry

The unique chemistry of boron allows for the utilisation of novel building-blocks which are not traditionally found in medicinal chemistry. The pharmaceutical industry has begun to exploit boronic acid derivatives as new drugs and several research groups are also exploring 1,2-azaborines and icosahedral boranes known as carboranes as boron-based structural motifs, with great promise for innovative drug design. Recent advances in the medicinal chemistry of these three important boron moieties are highlighted and illustrated with selected examples.