Nickel 0-catalyzed cross-coupling of alkyl arenesulfonates with aryl Grignard reagents.
The nickel-catalyzed cross-coupling reactions of neopentyl arenesulfonates with arylmagnesium bromides, involving nucleophilic aromatic substitution of alkyloxysulfonyl groups by aryl nucleophiles, take place in high yields. Optimal efficiencies are obtained by adding 3 + 2 equiv of the Grignard reagent to a mixture of dppfNiCl(2) and the sulfonate in refluxing THF. Neopentyl arenesulfonates are useful sources of the electrophilic aryl groups in these transition metal-catalyzed cross-coupling reactions. Aryl sulfonates are inappropriate due to their ambident reactivity under the reaction conditions. This new cross-coupling reaction can be used for the creative elimination of alkyloxysulfonyl groups from aromatic compounds and for the preparation of unsymmetric terphenyls and oligophenyls.
Cho
Chul-Hee
CH
Department of Chemical Engineering, Chung-Ang University, Huksuk-Dong 221, Dongjak-Ku, Seoul 156-756, South Korea.
Yun
Hee-Sung
HS
Park
Kwangyong
K