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Updated: Aug 8, 2026

Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Synthesis of angular triquinanes from 1-Alkynylbicyclo[3.2. 0]hept-2-en-7-ones. A tandem alkoxy-cope ring
S K Verma1, E B Fleischer, H W Moore
1Department of Chemistry, University of California, Irvine, Irvine California 92697-2025, USA.
Abstract:
Addition of ethenyllithium reagents to the carbonyl group of dialkyl squarate-derived 1-alkynylbicyclo[3.2.0]hept-2-ene-7-ones (15), followed by a TBAF workup, results in a low-temperature anion-accelerated alkoxy-Cope rearrangement which proceeds by way of a strained cyclic allene intermediates (e.g.,17). This leads to the formation of angularly fused triquinanes (e.g., 20) in which each of the rings is functionally differentiated. Bicyclo[6.3. 0]undecadienones (e.g., 36) are the major products when the reactions are quenched with aqueous bicarbonate rather than TBAF. Under analogous conditions 2-alkylidene-1-alkynylbicyclo[3.2. 0]heptan-7-ones also give bicyclo[6.3.0]undecadienones by a mechanism that was established to involve a 1,5-hydrgen shift in a strained allene intermediate. The synthetic scope and mechanism of these and related transformations are discussed.
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