Spiro[4.4] and spiro[4.5] lactones from phthaloyl chloride and 1,4- and 1,5-bis-nucleophiles
Abstract
Phthaloyl chloride reacts with the 1,4-bis-nucleophiles 3 to give spiro[4.4] lactones 7 and 9 and with the 1,5-bis-nucleophiles 10 to give spiro[4.5] lactones 12, as proved by X-ray crystallography, and not the 8- and 9-membered heterocyclic systems previously claimed.