Asymmetric Synthesis of a Bicyclo[4.3.0]nonene Derivative Bearing a Quaternary Carbon Stereocenter: Desymmetrization of σ-Symmetrical Diketones through Intramolecular Addition of an Alkenyl Anion

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3667-3674
Author(s):  
Tomoyuki Yoshimura ◽  
Yuki Enami ◽  
Jun-ichi Matsuo

The enantioselective synthesis of a bicyclo[4.3.0]nonene derivative bearing a quaternary carbon stereocenter is achieved by employing a desymmetrization strategy involving an intramolecular addition. The intramolecular nucleophilic addition of a highly reactive carbanion generated from an alkenyl iodide in the presence of a chiral ligand occurs with discrimination of two keto carbonyl groups to give the corresponding bicyclic compound in 81% yield and 39% ee. Asymmetric synthesis via an intramolecular desymmetrization strategy using a chiral ligand–carbanion complex represents a complementary approach to using chiral organocatalysts or chiral ligand–transition-metal complexes.

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3140-3152
Author(s):  
Kamal Kumar ◽  
Mohammad Rehan ◽  
Jana Flegel ◽  
Franziska Heitkamp ◽  
Jorgelina L. Pergomet ◽  
...  

An enantioselective hetero-Diels–Alder reaction of alkylidene­ oxindoles and 2-aza-3-silyloxy-1,3-butadienes, catalyzed by divalent transition metal complexes with N,N′-dioxide ligands offered an efficient access to natural-product-based 3,3′-piperidinoyl spiroox­indole class of small molecules. exo-Cycloadducts formed via stereospecific cycloaddition with Z-olefin displayed potent activity in modulation of hedgehog pathway.


ChemInform ◽  
2010 ◽  
Vol 23 (6) ◽  
pp. no-no
Author(s):  
YU. N. BELOKON' ◽  
V. I. MALEEV ◽  
S. O. VIDENSKAYA ◽  
M. B. SAPOROVSKAYA ◽  
V. A. TSYRYAPKIN ◽  
...  

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