We describe an alternative and more sustainable method for the synthesis of 2,2′-disubstituted 3,3′‑biindoles starting from 2,2’-diaminotolanes and (hetero)arylaldehydes. The key feature of the approach is the use of an acidic DES able to exploit ...
Enantioselective Synthesis of [b]‐Annulated Azepane Scaffolds
Von Wiley-VCH zur Verfügung gestellt
Optically active α-allyl-β-oxoesters are submitted to olefin cross metathesis and subsequent exhaustive hydrogenation and reductive amination to furnish [b]-annulated azepane derivatives.
Cyclopenta-, benzo-, and cyclohepta[b]-annulated azepane scaffolds were prepared in two steps from optically active cyclic α-allyl-β-oxoesters. The first step was ruthenium-catalyzed olefin cross metathesis with acrylonitrile. The second step was palladium-catalyzed dihydrogenation which consists of three consecutive processes: The hydrogenation of the C−C double and C−N triple bonds was followed by the reductive amination via the iminium ion formed in situ from the primary amino function and the endocyclic carbonyl group. This last step gave, stereoselectively, the annulated azepanes with relative trans-configuration. The amino function and the ester group define two points for further diversification of the scaffolds. The trifluoroacetyl derivatives allowed to establish the enantiopurity of the products to be 97–98 % ee by GLC on a chiral phase. The relative trans-configurations and in one case also the absolute (R,R)-configuration was established by X-ray crystallography.Zum Volltext
Jetzt nächsten Artikel lesen:
Überprüfung Ihres Anmeldestatus ...
Wenn Sie ein registrierter Benutzer sind, zeigen wir in Kürze den vollständigen Artikel.