NOVEL PALLADIUM-CATALYZED CARBONYLATION OF ORGANIC HALIDES BY CHLOROFORM AND ALKALI

Aromatic, vinylio, and benzylic halides were catalytically carbonylate d by CO generated in situ from chloroform and aqueous alkali, in the p resence of tertiary phosphine-palladium complexes (1-5 mol %). The car bonylation occurred at ambient temperature under N2, affording the cor responding carboxylic acids in up to 92% isolated yield. Under the sam e conditions, benzal bromide underwent catalytic reductive coupling to a 1:4 mixture of cis- and trans-stilbenes. A labeling experiment with (CHCl3)-C-13 showed that the source of the C1 unit in the carbonylati on is chloroform. Triphenylphosphine complexes of ruthenium, rhodium, and palladium were found to catalyze the alkaline hydrolysis of chloro form to carbon monoxide. A carbonyl complex, [(Ph3P)2Rh(CO)Cl], was sy nthesized by treatment of Wilkinson's catalyst with chloroform in the presence of KOH.