Pyranophane transannular diels-alder approach to (+)-chatancin: a biomimetic asymmetric total synthesis.
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.
Soucy
Pierre
P
Laboratoire de Synthèse Organique, Departement de Chimie, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Quebec J1H 5N4, Canada.
L'Heureux
Alexandre
A
Toró
András
A
Deslongchamps
Pierre
P
D032701:Biomimetics / Q000379:methods; D003500:Cyclization; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism
D004224:Diterpenes; D005663:Furans; D011714:Pyrans; C414662:chatancin