Another development for the Stille coupling reaction is to reduce the amount of
tin by making the reaction catalytic in tin (Scheme 16).35 In this reaction, tin hydride is
generated in situ from tin fluoride. Hydrostannylation of alkyne 1-64 results in a transvinyl
stannane that undergoes a Stille coupling with bromide 1-65. The tin bromide by-
16
product is then converted in situ to the tin fluoride, which is subsequently reduced in situ
to regenerate the tin hydride (Figure 7).