"Caffeone" is a relatively unknown word in the English language, but it is believed to be a combination of "caffeine" and "ketone". The IPA phonetic transcription for "caffeone" would be /kæ-fiː-oʊn/. The spelling of this word follows the traditional English spelling rules, with the initial "c" pronounced as a "k" sound, the two "f" sounds, and the "eo" combination pronounced as "ee-oh". With the increasing popularity of keto diets, it is possible that we may hear more of this unique word in the future.
Caffeol.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.