Chemo- and diastereoselective synthesis of spiro-dioxolanes from intermolecular carbonyl ylide cycloaddition with aryl aldehyde

Reaction of cyclic diazoamides and aromatic aldehydes having electron-donating or -withdrawing groups in the presence of rhodium(II) acetate catalyst at room temperature afforded the spiro-indolodioxolanes. A novel three-component reaction involving intermolecular carbonyl ylides has been demonstrated in a chemo- and diastereoselective manner.