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CO2 in a fix: Gold and copper complexes of N-heterocyclic carbenes recently enabled efficient direct carboxylation of (hetero)arenes having moderately acidic CH bonds under remarkably mild reaction conditions (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene).
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Lutz Ackermann (2011) studied this question.
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