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Upstream product

• 37428-56-1 (E)-3-bromo-2-buten-1-ol 
• 376393-18-9 (6S)-3-Ethynyl-6-hydroxy-2,4,4-trimethylcyclohex-2-enone 
• 80736-99-8 (S)-2,2,4,6,6-Pentamethyl-7,7a-dihydro-1,3-benzodioxol-5-(6H)-on 
• 80713-62-8 5-(1-methoxy-1-methylethoxy)-3-methyl-3E-penten-1-yne 
• 80713-53-7 (S)-Essigsaeure-<4-((E)-5-acetoxy-3-methyl-3-penten-1-inyl)-3,5,5-trimethyl-2-oxo-3-cyclohexen-1-yl>ester 

Downstream Products

• 80736-65-8 (6S)-6-Hydroxy-3-[(1E,3E)-5-hydroxy-3-methylpenta-1,3-dienyl]-2,4,4-trimethylcyclohex-2-enone 

Relevant academic research and scientific papers

Carotenoids and related polyenes. Part 6. Stereoselective synthesis of astaxanthin analogues and their antioxidant activities

Astaxanthin analogues having various lengths of polyene chains are stereoselectively synthesized and their singlet-oxygen-quenching activities are examined.

Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. III. Ein neues Konzept fuer die Synthese der enantiomeren Astaxanthine

A new and efficient concept for the total synthesis of (3S,3'S)- and (3R,3'R)-astaxanthin (1a and 1c, resp.) in high overall yield and up to 99,2percent enantiomeric purity is described.Key intermediates are the (S)- and (R)-acetals 10 and 17, respectively (Scheme 2).These chiral building blocks were synthesized via three different routes: a) functionalization of enantiomeric 3-hydroxy-6-oxo-isophorons 2 and 11, respectively (Scheme 2); b) optical resolution of 3,4-dihydroxy-compound 19 (Scheme 3), and c) fermentative reductions of 6-oxo-isophorone derivatives (Schemes 4 and 5). - The absolute configurations of the two intermediates 12 and 13 (Scheme 2) have been confirmed by X-ray analysis.The final steps leading to the enantiomeric astaxanthins are identical with those described for optically inactive astaxanthin .

Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus Oxo-isophoron. I. Modifizierung der Kienzle-Mayer-Synthese von (3S,3'S)-Astaxanthin

An efficient synthesis of (3S,3'S)-astaxanthin (1a) in high yield and optical purity starting from (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone (4) is reported.The absolute configuration of 1a, previously derived from ORD. data, has been confirmed by X-ray analysis of 5, a derivate of 6-oxo-isophorone (2).The key features of the improved synthesis are the two-step conversion of 4 to the key intermediate (4S)-2,6,6-trimethyl-4-hydroxy-2-cyclohexen-1-one (14), a new method for the partial reduction of the sterically hindered triple bond of (S)-6-hydroxy-3-(5-hydroxy-3-methyl-3-penten-1-ynyl)-2,4,4-trimethyl-2-cyclohexen-1-one (32), and Wittig olefination of the dialdehyde 1,6-dimethyl-1,3,5-octatrienedial (38) using phosphonium salt 37 with a free hydroxyl group.