REACTIONS VIA CARBONYL ANIONS - [4+1] CYCLOCOUPLING OF THE AZADIENYLLITHIUM WITH CARBON-MONOXIDE

Generation and reactions of carbonyl anions, relatively unknown species, have been studied. The reaction of beta-phenyl-2-azaethenyllithium 13, generated from aryl isocyanides 12 and t-BuLi, with carbon monoxide gives 3H-indole derivatives 18 in 42-44% yields after quenching with methyl iodide. Similarly,beta-phenyl-1-azaethenyllithium 21, obtainable by the addition of alkyllithium to benzonitriles 20; reacts with carbonmonoxide and methyl iodide to afford 1H-isoindole derivatives 27 in 73-81% yields. A 1,4-diazabutadienyl anion 35 gives a cyclic urea 39 on reacting with carbon monoxide and methyliodide. These reactions represent novel [4 + 1] cyclocoupling reactions of dienyl anions with carbon monoxide via carbonyl anions 14, 23, and 36 as the intermediates.