Diastereoselective synthesis of macrocycles incorporating the spiro-indolofurans and -indolodioxolanes

Generation of intramolecular macrocyclic carbonyl ylides from aldehyde group tethered to diazoamides in the presence of rhodium(II) acetate and their successful [3+2]-cycloaddition afforded the corresponding macrocycles incorporating spiro-indolofurans, -indolofuropyrroles, -indolofurofurans, and -indolodioxolanes in moderate to good yield with complete diastereoselectivity. The competition between the electrocyclization and [3+2]-cycloaddition reactions of macrocyclic carbonyl ylides was also demonstrated.