Terpene und Terpen‐Derivate, XXI. Synthese von rac ‐4,5‐Dihydro‐β‐curcumen‐4,5‐diol

Terpenes and Terpene Derivatives, XXI. – Synthesis of rac ‐4,5‐Dihydro‐β‐curcumene‐4,5‐diol Hydrolysis of the β‐curcumene monoepoxide 1 afforded the title compound 2 . – A second way started from the epoxy ketone 6 . Hydrolysis (→ 7 ), formation of the THP ethers (→ 8 , → 9 ), and reaction with homoprenyllithium leads to the allylic alcohol 3 . After further protection (→ 4 ), Birch reduction, and subsequent hydrolysis a 1:4 mixture of the diols 2 and ( E/Z )‐ 11 was isolated.