Lactone rhymes with:
aiton, bastone, briggstone, brimstone, ketone, moton, pistone, aiton, aon, bastone, briggstone, brimstone, cellphone, cerbone, citroen, gambone, glendon, halcyone, hendon, keown, ketone, marylebone, milhoan, moton, okon, pharaon, pistone, provolone, rendon, shadoan, shimon, shimone, smothermon, tabone
Lactone sounds like:
lactation, laughton, laxton, lecithin, leichtman, leighton, lewiston, lichten, lichtman, ligation, lighten, liquidation, listen, liston, location, lockdown, logsdon, logston, lusitania, luxton