Dihydrokavain

용도(+)-(S)-Dihydrokavain is a kavalactone found in kava beverages consumed by South Pacific islanders. Furthermore, roots and extracts of the kava plant have been used in herbal medicine to treat sleep disturbances, as well as stress and anxiety.

Starting from 2,3-O-isopropylidene-D-glyceraldehyde (2) as chiral material, the naturally occurring (S)-(+)-dihydrokavain (1a) was synthesized by a procedure that involves a sonochemical Blaise reaction as the key step. The absolute configuration of (S)-(+)-dihydrokavain (1a) is demonstrated for the first time by total synthesis from a chiral source. Its opposite enantiomer, (R)-(–)-dihydrokavain (1b), was also synthesized after inversion of the chiral center in a Mitsunobu reaction.A Total Synthesis of (+)- and (–)-Dihydrokavain with a Sonochemical Blaise Reaction as the Key Step