Abstract
A catalytic system consisting of 5 mol% CoCl2 and 10 mol% isoquinoline allows a convenient cross-coupling of benzylic zinc reagents with various aryl and heteroaryl bromides or chlorides leading to polyfunctionalized diaryl- and aryl-heteroaryl-methane derivatives.
Highlights
A catalytic system consisting of 5 mol% CoCl2 and 10 mol% isoquinoline allows a convenient cross-coupling of benzylic zinc reagents with various aryl and heteroaryl bromides or chlorides leading to polyfunctionalized diaryl- and aryl-heteroaryl-methane derivatives
The use of zinc organometallics is of special synthetic interest due to the high functional group compatibility of zinc reagents.[5]
Ingleson has described a transition metal free cross-coupling between relatively non-functionalized diarylzincs with benzylic bromides and chlorides performed in the absence of coordinating ethereal solvents.[9]
Summary
A catalytic system consisting of 5 mol% CoCl2 and 10 mol% isoquinoline allows a convenient cross-coupling of benzylic zinc reagents with various aryl and heteroaryl bromides or chlorides leading to polyfunctionalized diaryl- and aryl-heteroaryl-methane derivatives. We report a practical cobalt-catalyzed cross-coupling promoted by 10 mol% of isoquinoline between various benzylic zinc reagents with aryl and heteroaryl bromides or chlorides resulting in the formation of valuable diaryl- and arylheteroarylmethane derivatives.[10] Preliminary control experiments performed with benzylzinc chloride The treatment of benzylic zinc reagents (1a,b) in the presence of 5 mol% CoCl2 and 10 mol% isoquinoline with 4-bromobenzonitrile (3a) at 50 1C within 2 to 4 h is leading to the diarylmethane derivatives 4a,b in 77–82% (Table 2, entries 1 and 2).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have