Total Syntheses of Rhodiolosides A and D and of Sachalinols A-C

The glucosylated monoterpenoids (-)-rhodioloside A and (-)-rhodioloside D from the roseroot (Rhodiola rosea) have been synthesized for the first time. Glucosylation with tetrapivaloylglucosyl bromide proved superior to the use of tetraacetylglucosyl bromide or glucosyl iodides. Acid-catalyzed cyclization of a homoglycidol-type geraniol derivative afforded the monoterpenoid tetrahydrofuran (+)-sachalinol C from Rhodiola sachalinensis. The absolute configuration of (+)-sachalinol C requires revision. (-)-Sachalinol A and (-)-sachalinol B were also obtained.