56701-26-9Relevant articles and documents
Method for asymmetrically synthesizing glabridin with optical purity
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, (2020/07/15)
The invention discloses a method for asymmetrically synthesizing glabridin with optical purity, belonging to the field of organic synthesis. According to the invention, 7-hydroxychroman-4-one is usedas a raw material and is subjected to seven successive reactions including a protecting group protection reaction, an enol esterification reaction, an asymmetric addition reaction, a carbonyl reduction reaction, a phenolic hydroxyl protecting group removal reaction, a cyclization reaction and a demethylation reaction so as to finally prepare glabridin with optical purity. The optically pure glabridin is obtained by asymmetrically introducing a chiral center by using a palladium catalyst and an organophosphorus ligand; reaction conditions are mild; operation is convenient; and the method is suitable for industrial application. The raw material is easy to obtain and low in cost, and the product is good in yield and high in stereoselectivity.
A chiral pool approach for asymmetric syntheses of both antipodes of equol and sativan
Yalamanchili, Chinni,Chittiboyina, Amar G.,Chandra Kumar Rotte, Sateesh,Katzenellenbogen, John A.,Helferich, William G.,Khan, Ikhlas A.
, p. 2020 - 2029 (2018/03/21)
For the first time, both antipodes of the isoflavans, equol and sativan were synthesized in >98% ee with good overall yields starting from readily available starting materials. The chiral isoflavan, (?)-equol is produced from soy isoflavones, formonentin and daidzein by the action of intestinal bacteria in certain groups of population and other chiral isoflavans are reported from various phytochemical sources. To produce these chiral isoflavans in gram quantities, Evans’ enantioselective aldol condensation was used as a chiral-inducing step to introduce the required chirality at the C-3 position. Addition of chiral boron-enolate to substituted benzaldehyde resulted in functionalized syn-aldol products with >90% yield and excellent diastereoselectivity. Functional group transformations followed by intramolecular Mitsunobu reaction and deprotection steps resulted the target compounds, S-(?)-equol and S-(+)-sativan, with high degree of enantiopurity. By simply switching the chiral auxiliary to (S)-4-benzyloxazolidin-2-one and following the same synthetic sequence the antipodes, R-(+)-equol and R-(?)-sativan were achieved. Both enantiomers are of interest from a clinical and pharmacological perspective and are currently being developed as nutraceutical and pharmacological agents. This flexible synthetic process lends itself quite readily to the enantioselective syntheses of other biologically active C-3 chiral isoflavans.
Synthetic access to optically active isoflavans by using allylic substitution
Takashima, Yuji,Kaneko, Yuki,Kobayashi, Yuichi
experimental part, p. 197 - 207 (2010/03/03)
A general approach to the (S)- and (R)-isoflavans was invented, and efficiency of the method was demonstrated by the synthesis of (S)-equol ((S)-3), (R)-sativan ((R)-4), and (R)-vestitol ((R)-5). The key step is the allylic substitution of (S)-6a (Ar1=2,4-(MeO)2C6H3) and (R)-6b (Ar1=2,4-(BnO)2C6H3) with copper reagents derived from CuBr·Me2S and Ar2-MgBr (7a, Ar2=4-MeOC6H4; 7b, 2,4-(MeO)2C6H3; 7c, 2-MOMO-4-MeOC6H3), furnishing anti SN2′ products (R)-8a and (S)-8b,c with 93-97% chirality transfer in 60-75% yields. The olefinic part of the products was oxidatively cleaved and the Me and Bn groups on the Ar1 moieties was then removed. Finally, phenol bromide 9a and phenol alcohols 9b,c underwent cyclization with K2CO3 and the Mitsunobu reagent to afford (S)-3 and (R)-4 and -5, respectively.
