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Stereo- and Regioselective Synthesis of Molecular Baskets. | LitMetric

Stereo- and Regioselective Synthesis of Molecular Baskets.

J Org Chem

Department of Chemistry and Biochemistry , The Ohio State University, 100 W. 18th Avenue , Columbus , Ohio 43210 , United States.

Published: April 2019

AI Article Synopsis

Article Abstract

We describe a stereoselective method for obtaining multigram quantities of molecular basket 1 in overall 11% yield, using inexpensive cyclopentadiene and diethyl fumarate as starting materials. First, an asymmetric synthesis of enantioenriched bromo(trimethylstannyl)alkene (-)-8 was accomplished by the stereoselective bromination of dibromonorbornene (+)-4 guided by anchimeric assistance and subsequent syn- exo-elimination of tetrabromonorbornane (-)-5a as the key steps. Subsequent Cu(I)-catalyzed cyclotrimerization of (-)-8 was optimized to give 1 in 85% yield and 1:1 ratio of diastereomers. Importantly, the results of our mechanistic experiments were in line with the cyclotrimerization occurring in a chain-type fashion with racemization of a Cu(I) homochiral dimeric intermediate, reducing the stereoselectivity of the transformation. Enabled by more facile access to molecular baskets of type 1 , a range of recognition studies can now be completed for producing novel supramolecular catalysts, organophosphorus scavengers, and nanostructured materials.

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Source
http://dx.doi.org/10.1021/acs.joc.9b00330DOI Listing

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