Stereoselective synthesis of 4-dehydroxydiversonol employing enantioselective palladium-catalysed domino reactions.
The stereoselective synthesis of 4-dehydroxydiversonol (4) employing enantioselective palladium-catalysed domino processes such as the domino Wacker-Heck and the domino Wacker-carbonylation reaction for the formation of the central chroman moiety is described. Thus, reaction of 8 with palladium(II) trifluoroacetate [Pd(OTFA)2] in the presence of carbon monoxide, methanol and the 2,2'- bis(oxazolin-2-yl)-1,1'-binaphthyl (BOXAX) ligand 17 led to 19 in 80% yield and 96% ee. Similarly, the chroman 7 was prepared using 8 and methyl acrylate (9) as starting material. Hydrogenation of the double bond, oxidation of the benzylic methylene group and intramolecular acylation of chromanone 6 provided the tetrahydroxanthenone core 5, from which the synthesis of 4 was completed. The relative configuration of 4 could be established by crystal structure analysis.
Tietze
Lutz F
LF
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen (Germany), Fax: (+49) 551-39-9476.
Spiegl
Dirk A
DA
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen (Germany), Fax: (+49) 551-39-9476.
Stecker
Florian
F
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen (Germany), Fax: (+49) 551-39-9476.
Major
Julia
J
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen (Germany), Fax: (+49) 551-39-9476.
Raith
Christian
C
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen (Germany), Fax: (+49) 551-39-9476.
Große
Christian
C
Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen (Germany).
D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D006900:Hydroxylation; D008958:Models, Molecular; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism; D044004:Xanthones / Q000138:chemical synthesis* / Q000737:chemistry
D000588:Amines; D044004:Xanthones; C514121:diversonol; D010165:Palladium