Herstellung diastereomerenreiner l- oder u-konfigurierter 1-hydroxybenzylierter Tetrahydroisochinolin-Vorläufer für Aporphin-, Protoberberin-, Quettamin- und Phthalid-Alkaloide (Stereoselektive Synthese von (±)-Ushinsunin und (±)-Oliverolin)
6,7-Dialkoxy-1-bromomagnesio-2-pivaloyl-tetrahydroisoquinolines (THIQ), prepared as previously described for the unsubstituted reagent, are added to bromo-, methoxy-, and ethoxycarbonyl-substituted benzaldehydes to give 1-hydroxybenzylated THIQs of u-configuration exclusively (2a-4a, 5). These are...
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| Main Authors: | , |
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| Format: | Article |
| Language: | deu |
| Published: |
Swiss Chemical Society
1985-08-01
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| Series: | CHIMIA |
| Online Access: | https://www.chimia.ch/chimia/article/view/9676 |
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| Summary: | 6,7-Dialkoxy-1-bromomagnesio-2-pivaloyl-tetrahydroisoquinolines (THIQ), prepared as previously described for the unsubstituted reagent, are added to bromo-, methoxy-, and ethoxycarbonyl-substituted benzaldehydes to give 1-hydroxybenzylated THIQs of u-configuration exclusively (2a-4a, 5). These are converted to the isomeric pivalates either with retention (u-2b-4b) or with inversion of configuration (l-2b-4b). The diastereomers u-3b and l-3b are hydrolized to the free aminoalcohols (3, R1 = R2 = H) which are N-methylated (→3, R1 = CH3, R2 = H) and cyclized photochemically to the known alkaloids (±)-ushinsunine (u-6) and (±)-oliverolin (l-6), respectively. – The highly functionalized, diastereomerically pure 1-hydroxybenzylated THIQ derivatives described here are versatile precursors for the syntheses of aporphine (see 6), protoberberine, quettamine, and phthalid (see 5) alkaloids.
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| ISSN: | 0009-4293 2673-2424 |