A Metathetic Approach to [5/5/6] Aza-Tricyclic Core of Dendrobine, Kopsanone, and Lycopalhine A Type of Alkaloids

Abstract

A concise synthetic approach to [5/5/6] tricyclic pyrrolidine core of dendrobine is reported. This methodology relies on the construction of β-hydroxylactams by NaBH₄-I₂ reduction followed by reaction of allylsilane with the aid of Lewis acid to generate alkenyl lactams in good yields. Further, ring-opening metathesis (ROM) followed by ring-closing metathesis (RCM) were used to assemble the [5/5/6] aza-tricyclic skeleton of dendrobine. This short synthetic route has been expanded to assemble tricyclic [5/5/8] system with pentenylboronic acid.

Key words

dendrobine - [5/5/6] aza-tricyclic - metathesis - allylation - NOE - BF₃·OEt₂

• References

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