2209-02-1Relevant academic research and scientific papers
Chemoenymatic Synthesis of the Eight Stereoisomeric Muscarines
Amici, Marco De,Micheli, Carlo De,Molteni, Giorgio,Pitre, Davide,Carrea, Giacomo,et al.
, p. 67 - 72 (2007/10/02)
Efficient synthesis of the eight stereoisomers of muscarine have been accomplished by dehydrogenase-catalyzed reduction of iodo ketones (+/-)-3a and (+/-)-3b. 3α,20β-Hydroxysteroid dehydrogenase from Streptomyces hydrogenans exhibited high enantiomeric and diastereotopic selectivity for (+/-)-3a, yielding an equimolar mixture of iodo alcohol (-)-4 (2S,4S,5S) (96percent ee) and iodo ketone (+)-3a (2R,5R) (96percent ee) which was reduced by sodium borohydride to a mixture of (+)-4 and (+)-5. 3β,17β-Hydroxysteroid dehydrogenase from Pseudomonas testosteroni reduced (+/-)-3b wih high diasterotopic selectivity to give an equimolar mixture of iodo alcohols (+)-6 (2R,4S,6S) (>99percent ee) and (-)-7 (2S,4S,5R) (81percent ee).Synthesis of the remaining iodo alcohols was achieved by applying the Mitsunobo procedure to (-)-4, (-)-7, and (+)-6.The enantiomeric excess of intermediates 4-7 was determined by HPLC analysis of the (R)-(+)-MTPA esters.The chiral iodo alcohols 4-7 were then transformed into the final derivatives by conventional chemical manipulations.
Chelation-Controlled Synthesis of (+/-)-Muscarine
Still, W.Clark,Schneider, Josef A.
, p. 3375 - 3376 (2007/10/02)
The chelation controlled addition of Grignard reagents to chiral α-alkoxy aldehydes to give threo diol derivatives is synthetically useful in highly oxygenated systems and is used here as the key step in a novel synthesis of (+/-)-muscarine from cyclopentadiene.
