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Updated: Jun 14, 2025

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
1,6-Reduction-Type Hydride Shift/Cyclization Process without Adjacent Heteroatom: Stereoselective Synthesis of
Wakana Matsui1, Takayuki Matsuno1, Ikuma Takiguchi2
1Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan.
Abstract:
We report stereoselective access to hexahydrofluorene derivatives with three contiguous stereogenic centers based on a hydride-shift-triggered C(sp3)-H bond functionalization (internal redox reaction). The key process is an unprecedented 1,6-reduction-type hydride shift at the position without an adjacent heteroatom. When alkenylidene malonates having a methine group adjacent to a para-methoxyphenyl group were treated with a catalytic amount of SnCl4, an internal redox reaction and an intramolecular Friedel-Crafts reaction proceeded successively to afford hexahydrofluorene derivatives with three contiguous stereogenic centers in good chemical yields with excellent diastereoselectivities. Additional experiments and DFT calculations revealed that the interconversion between the cis- and trans-isomers was responsible for the high yields and diastereoselectivities.
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