Formal Asymmetric Synthesis of Echinopine A and B

Abstract

Enticing structures: The formal syntheses of 1 and 2 were accomplished by using a cascade strategy involving an enyne cycloisomerization reaction and an intramolecular Diels–Alder reaction starting from 3. The resulting 4 underwent a late-stage ring contraction to enable the preparation of a reported advanced intermediate, thereby constituting a formal synthesis of the structurally intriguing title compounds. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.