Asymmetric synthesis XXVIII : Hydroxylated benzoquinolizidine analogues of podophyllotoxin via the (CN(R,S) method.
1993; Elsevier BV; Volume: 49; Issue: 19 Linguagem: Inglês
10.1016/s0040-4020(01)89913-0
ISSN1464-5416
AutoresPhilippe Lienard, Jean‐Charles Quirion, Henri‐Philippe Husson,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoThe condensation of 2-cyano-6-phenyloxazolopiperidine synthon (−)-5 with piperonal, gave after reduction, the optically pure pivotal amino-alcohol 8. Two strategies were developed to prepare the epimeric azapodophyllotoxin analogues 2 and 3 via Grignard reactions on an iminium ion generated from the common intermediate 8. The first strategy was based on an intramolecular reaction while the second involved a stereocontrolled addition reaction on iminium ion 20.
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