Toward the Synthesis of Pestalustaine A: Structural Revision and Formation of Original Strained Tricyclic Architectures
Abstract
ABSTRACT We report our quest toward the total synthesis of the reported structure of the sesquiterpene pestalustaine A and its unprecedented tricyclic skeleton. Our retrosynthesis involved a transannular Michael addition of a 1,3‐keto‐ester and enal‐containing bicyclo[4.4.1]undec‐3‐ene obtained from the ring expansion of a chiral γ,γ−disubstituted cyclohexanone and stereoselective Hosomi‐Sakurai reaction. Serendipity allowed us to uncover powerful divergent and unexpected cyclizations of this bicycle in ionic or oxidative conditions, giving access to complex tricyclic architectures such as tricyclo[5.2.1.1 2,5 ]undecane, octahydro‐1,5‐methanonaphthalene, octahydro‐12,6‐methanonaphthalene frameworks, and the octahydro‐1,5‐methanoazulene reported skeleton of pestalustaine A. The present synthetic study also led us to note a discrepancy between the reported structure of pestalustaine A and the 2D NMR data, which led us to propose a revised structure of the natural product to a caryophyllene‐type framework, a reassignment supported by computational prediction of NMR chemical shifts.
Article Details
Authors (13)
Wei Cao
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering
Alicia Ross
Department of Chemistry University of California Davis Davis California USA
Jean‐Pierre Baltaze
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) Orsay France
Régis Guillot
Institut de Chimie Moléculaire et des Matériaux d’Orsay, CNRS
Menglin Xu
State Key Laboratory of Chemical Safety College of Chemistry and Chemical Engineering China University of Petroleum (East China) Qingdao People's Republic of China
Rongzhen Qin
State Key Laboratory of Chemical Safety College of Chemistry and Chemical Engineering China University of Petroleum (East China) Qingdao People's Republic of China
Bingcheng Yang
State Key Laboratory of Chemical Safety College of Chemistry and Chemical Engineering China University of Petroleum (East China) Qingdao People's Republic of China
Isabel Wong
Sacramento City College Sacramento California USA
Katayoon Formul
Sacramento City College Sacramento California USA
Cyrille Kouklovsky
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) Orsay France
Dean J. Tantillo
Department of Chemistry, University of California Davis, One Shields Ave. Davis, Sacramento, California 95616, United States
Vincent Gandon
Guillaume Vincent
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) Orsay France