HETEROCYCLIC SYNTHESIS USING NEW HETERODIENOPHILES

This chapter explains that heterodienophiles represent a very important class of compounds that are enjoying considerable use in organic chemistry, especially for the formation of heterocycles via cycloaddition reactions. This chapter focuses on the systems of the general formula RX=Y. Most of these systems are transient intermediates that cannot be isolated. It is only in the last few years that the chemistry of these systems has been explored in a systematic way. Within this series of compounds, thioaldehydes and RCH=S are by far the most widely used in synthesis. The chapter also explores that the preparative routes to selenoaldehydes and telluroaldehydes have invariably been developed on the analogous thio systems. It reviews that the wide range of thionitroso compounds, RN=S, are now firmly established as reactive intermediates. © 1992, Elsevier Science Publishers B.V.