Synthese und Chiralität der enantiomeren 6‐Hydroxy‐α‐ionone sowie von cis‐ und trans‐5,6‐Dihydroxy‐5,6‐dihydro‐β‐iononen

Synthesis and Chirality of the Enantiomeric 6‐Hydroxy‐α‐ionones and of cis‐ and trans‐5,6‐Dihydroxy‐5,6‐dihydro‐β‐ionones We describe the synthesis of (−)‐(5R,6S)‐5,6‐dihydroxy‐5,6‐dihydro‐β‐ionone (10) and (+)‐(5S,6S)‐5,6‐dihydroxy‐5,6‐dihydro‐β‐ionone (12). The absolute configuration of these compounds has been established by correlation with (R)‐4‐hydroxy‐β‐ionone (1). Therefore, by comparison, the 5,6‐dihydroxy‐5,6‐dihydro‐β‐ionone recently isolated from Rehmannia glutinosa var. purpurea by Endo et al.[4] has the (5R,6R)‐configuration ((−)−12). The same holds for the 5‐β‐D‐glucopyranoside (15) isolated from Aeginetia indica var. gracilis.