Diversity-oriented synthesis; a challenge for synthetic chemistsElectronic supplementary information (ESI) available: Excel file of all the FDA new molecular entities between the years 1998 and July 2003, and new drug approvals between the years 1990 and 2002. See http://www.rsc.org/suppdata/ob/b3/b310752n/

The efficient, simultaneous synthesis of structurally diverse compounds, better known as diversity-oriented synthesis (DOS), is not obvious, and remains a challenge to synthetic chemistry. This personal account details why DOS has such enormous implications for the discovery of small molecules with desired properties, such as catalysts, synthetic reagents, biological probes and new drugs, Also, I describe the evolution behind the current state-of-play of DOS.