Alkynes

This chapter focuses on the differences between alkynes and alkenes, particularly those that affect synthetic work. It explains that one difference concerns the CC double bond, which is usually created from saturated intermediates by elimination but is formed in a different way in alkynes. In these, ethene is widely used in building up the higher members and other compounds containing the triple bond. The chapter observes that alkynes are less reactive than alkenes, but with nucleophiles, the relative reactivity is reversed as simple alkenes do not undergo nucleophilic addition while simple alkynes undergo few additions. It discusses the hydrogenation of an alkyne with a poisoned catalyst that stops at the alkene stage.