A Divergent Synthesis of Spiroindenes via Ligand‐Controlled [3+2]/[4+2] Cycloadditions of Zwitterionic π‐Propargyl Palladium Species with Benzofulvenes

Chinese Journal of Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 5, 2025

Comprehensive Summary A divergent synthesis of spiroindenes through a palladium catalyzed cycloaddition between zwitterionic π‐propargyl species and benzofulvenes in moderate to good yields has been disclosed along with functional group compatibility broad substrate universality. This protocol features highly regioselective switchable process [3+2] [4+2] cycloadditions controlled by phosphine ligands different bite angles. The reaction mechanism clarified mechanistic studies DFT calculations, rendering that the coordination modes substrates angle play critical roles product regioselectivity.

Language: Английский

Controlled chain-growth polymerization via propargyl/allenyl palladium intermediates

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: March 13, 2025

In contrast to allyl palladium complexes, propargylic/allenylic species display complex reactivities that limit their implementation in polymer chemistry, especially for chain-growth polymerizations. Here we report an example of controlled polymerization via propargyl/allenyl intermediates. Vinylidenecyclopropane 1,1-dicarboxylate (VDCP), a unique allenylic electrophile, selectively reacts the σ-allenyl rather than more common π-propargyl pathway, thereby unlocking process. Based on this concept, precise synthesis alkyne-backbone polymers is realized, featuring fast rate, high molecular weight, narrow dispersity, chemoselectivity, and excellent end-group fidelity. We demonstrate preparation unsaturated macromolecules with advanced sequences architectures using method, including block, gradient, graft copolymers. chemistry. Here, authors

Language: Английский

Theoretical Studies on the Reaction Mechanism for the Cycloaddition of Zwitterionic π-Allenyl Palladium Species: Substrate-Controlled Isomerization

Molecules, Journal Year: 2024, Volume and Issue: 30(1), P. 103 - 103

Published: Dec. 30, 2024

Zwitterionic π-allenyl palladium species are newly developed intermediates. A substrate-controlled step existed in the cycloaddition of zwitterionic with tropsulfimides or tropones. With assistance previously experimental studies, allenyl/propargyl was provenly found by HRMS. Further DFT calculation studies show that generated through oxidative addition Pd(0), which can be promoted Lewis acid like Yb(OTf)3, and more likely undergoes an outer sphere nucleophilic attack. The isomerization is caused difference dissociation energy between intermediation tropones, forming specificity.

Language: Английский