Ketenes in Polymer‐Assisted Synthesis

Abstract

Since its inception, ketene chemistry has developed into a unique and well-established source of useful transformations for conventional synthetic organic chemistry. It is, therefore, not surprising that soon after their movement from the realm of peptide and peptoid libraries to that of small molecules, combinatorial chemists have sought the benefits of ketene chemistry to satisfy their own synthetic needs. The ability of these versatile molecules to undergo reactions with nucleophiles, and to participate in cycloadditions and cyclocondensations, has been utilized for the preparation of diverse heterocyclic compounds, and has added to the advantages of polymer-assisted synthesis for rapid purification. Different types of ketenes and different methods for their generation have been involved, which illustrates the potential diversity of the chemistry. There is now a better grasp of the effect of the fragility of these sometimes transient molecules on the reactions involving solid supports, and this augurs well for the application of some of the more recent developments in ketene chemistry to the generation of small-molecule libraries.

Ketene Chemistry after 100 Years: Ready for a New Century

“…Ketene chemistry has already experienced many new discoveries in the 21st century, as described here, and in other developments, including polymer‐assisted chemistry,27 photolithography,28a–28c and drug discovery 28d. With these vigorous beginnings the next 100 years of ketene chemistry can be expected to show many more new and useful developments that exploit the unique structure and reactivity of this family.…”