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Updated: Aug 29, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Pyranophane transannular diels-alder approach to (+)-chatancin: a biomimetic asymmetric total synthesis
Pierre Soucy1, Alexandre L'Heureux, András Toró
1Laboratoire de Synthèse Organique, Departement de Chimie, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Quebec J1H 5N4, Canada.
Abstract:
An asymmetric total synthesis of (+)-chatancin was achieved via a transannular Diels-Alder (TADA) reaction of an in situ generated macrocyclic pyranophane pseudobase. The presented route constitutes the second of two proposed biosynthetic pathways that involves a TADA reaction. It links this diterpene biogenetically to the cembranoids. A set of TADA selection rules that rationalize the formation of (+)-chatancin from a dynamic equilibrium of four 2-hydroxy-2H-pyrane bicycles and their 16 potential TADA transition states are also outlined. Beyond the TADA reaction, highlights of the synthetic work include the assembly of a chiral acyclic macrocyclization substrate from (S)-citronellol and an efficient macrocyclization via a beta-ketosulfoxyde/enone Michael addition.
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