Reductions par les hydrures et hydroboration etude de la stereoselectivite de nouvelles voies d'acces aux 3-arylmethyl-4-chromanols (Homoisoflavanols)
✍ Scribed by Michel Gomis; B. Serge Kirkiacharian
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- French
- Weight
- 758 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
The reduction of 3-aryhnethyl-4-chromanones by sodium borohydride, lithium trktert-butoxyaluminum hydride and hydroboration followed by oxydation of 3-benzyl-Chydroxy-wumarines lead to mixtures of Cis and Trans diastereoisomers of 3-aryhnethyl4chromanols (homoisoflavanols). The reduction of 3-aryhr&yl4chromanones by diborane or bitt-tat-butylthioethane diborane (BTED) is stereoselective and forms Ci and Trans diaskreoisomers with excellent yields ; the use of 9-horabicyclo-[3.3.1.]-nonane (9-BBN) decreases this stereoselectivity. R&u& -par le borohydrure de sodiim et l'hydmre de tri-tert-bu-La reduction des 3-ary~yl4chrones toxyahmkium lithium ainsi que l'hydroboration suivie de l'oxydation des 3-benxyl4hydroxy-wumarinoumarines wnduisent i de-s m&nges de 3-ary~thyl4chromanols (homoisoflavanols) diastMoiiom&res Cis et Trans. La r&h&on des 3-aryhrkthy14chromanones par le diborane ou le his-tert-butylthie diborane (BTED) forme lea diast& r&isomkes Cii avec d'excellents rendements ; l'emploi du 9-bora biiclo-[3.3.1 .]-nonane (9-BBN) diminue cette s~s~lectivti.