withdrawing anisole derivative delivered the corresponding
product 3ea in 51% yield. The electron-poor phenyl
thiocyanate containing the electron-withdrawing CF3 group
was converted to the desired product 3fa in only 17% yield.
Decreasing the reaction temperature to 25 °C increased the
yield up to 25%. Different halogens at the benzene ring revealed
only a small influence on the reactivity. The desired products
could be obtained in moderate yields ranging from 50% to 61%
(3ga−3ja). However, these examples represent products which
show difficulties in several other biaryl thioether syntheses.
Finally, thiocyanates with extended π-systems were employed
affording naphthalene derivative 3ka in 61% yield and indole
derivative 3la in 52% yield, respectively. In contrast to previous
examples trimerization of the aryne was a noteworthy side
reaction. Because of the formation of a large amount of
triphenylene side product, 4.5 equiv of 2a were required to
achieve a satisfactory conversion in the latter case.