Azole-Transfer Reactions to Carbon Atoms

Selected reactions of hydride-bridged dialuminium complex 169 are presented below <20010M4301>. The reactions between complex 169 and 1 equiv of diphenylacetonitrile or benzophenone result in the bridged hydride transfer to the nitrile or carbonyl carbon atom, while those between compound 169 and 1 equiv of 3,5-diphenylpyr-azole or diphenylmethanol cause elimination of the bridged hydride ion (Scheme 3). 

DFT calculations have been reported of the copper-catalysed reaction of A-methyl indoles with amides, which result in amidation at the 2-position. The results show that a concerted metalation—deprotonation pathway does not explain the observed regioselectivity. Instead, a four-centre reductive elimination involving the transition state (80) is proposed. The reaction is likely to be completed by proton transfer from the amidated carbon atom to the butoxy ligand. Copper-catalysed reaction of azoles or polyfluoroarenes with sulfoximines may produce A-aryl sulfoximines. Owing to the mild reaction conditions, enantiopurity in the starting sulfoximine is retained in products such as (81). 

A straightforward conversion of 2-unsubstituted imidazole 3-oxides (66) into the corresponding imidazole-2-thiones (67) is achieved by the reaction with 1 in dichloromethane at rt (eq 28). This sulfur-transfer reaction can be applied to other azole (V oxides with an unsubstituted carbon atom next to the Atoxide position. 

---