Abstract:
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We report the alkynylation of C(sp2)−H bonds
with bromoalkynes (inverse-Sonogashira reaction) directed by
synthetically useful ester, ketone, and ether groups under
rhodium catalysis. Other less common directing groups such as
amine, thioether, sulfoxide, sulfone, phenol ester, and
carbamate are also suitable directing groups. Mechanistic
studies indicate that the reaction proceeds by a turnoverlimiting
C−H activation step via an electrophilic-type
substitution. |