Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. II. Synthese von (3 S, 3′S)‐Astaxanthin

Abstract

Synthesis of optically active natural carotenoids and structurally related compounds. Synthesis of (3S,YS)-astaxanthin SummaryThe syntheses of rac. astaxanthin, (3 S , 3's)-astaxanthin(]), its 1 5 4 s isomer

Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6‐Oxo‐isophoron. II. Ein neues Konzept für die Synthese von (3RS, 3′RS)‐Astaxanthin

“…Einleitung. -Kurzlich berichteten wir [l] iiber die Modifizierung einer von Kienzle & Muyer [2] beschriebenen Synthese von (3S, 3's)-Astaxanthin (la) zu einem effizienten, technisch anwendbaren Verfahren. Daran unbefriedigend geblieben war die durch den prinzipiellen Syntheseplan bedingte, relativ hohe Stufenzahl (14).…”

Enzymatic Preparation of Chiral 4-Hydroxy-2,2-dimethyl-1-cyclohexanone as a Chiral Building Block

“…GC (130°C, 30ml ofN2/min) tR: 10.1 min (100%). 3, (II). To a solution of (± )-12 (5.68 g) in acetone (60 ml), Jones reagent (2.67 M, 17.5 m!)…”

“…Elution with hexane-ethyl acetate (15: I and 10: I) gave the trimethyl derivative (1.84 g, 76% from (S)-la) as a diastereomeric mixture and the recovered (S)-lc (0.42g, 18% from (S)-la), respectively. After exchanging the THP-oxyl group with the acetoxyl group in the usual manner, the trimethyl derivative was converted to ( + )-(R)-4 according to the method reported by Kienzle et al,3) [ocl1° +48.1 ° (c=0.786,EtOH) [-46.7° (c= 1.0, EtOH?) and -49.0° (c= 1.0, EtOH)IO) for (S) -4 of 100% e.e.l.…”

“…The stereochemistry and optical purity of ( -)-la were further reconfirmed by converting ( -)-la to chiral4 according to the reported method. 3 ) Comparing the specific rotation of the obtained (+ )-(R)-4 with that of an authentic specimen of (-)-(S) -4,1°) it was concluded that (-)-la had an (S)-configuration and was optically pure. The 2.6-A crystal structure of P-450 camphor hydroxylase (P-450 cam) isolated from Pseudomonas putida was first reported by Poulos et alY) More abstracted models of the camphor binding site are depicted in Fig.…”

Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6‐Oxo‐isophoron. V. Synthese von Astacin

“…Butyllithium-~aan'ante. Zu 217 g (1,0 mol) (3-Methyl-2-penten-4-yn-1-yl)-trimethylsilylather [24] in 1 1 abs. THF wurden bei -10" in 20 Min.…”