Palladium Tandem Catalysis in the Atropodiastereoselective Synthesis of Indenes Bearing Central and Axial Chirality

Cyril Borie (1) , Nicolas Vanthuyne (2) , Michèle.P Bertrand (1) , Didier Siri (1) , Malek Nechab (1)

1 ICR - Institut de Chimie Radicalaire
2 ISM2 - Institut des Sciences Moléculaires de Marseille

The conversion of propargylic carbonates into allenes via Pd-catalyzed coupling with arylboronic acids, followed by tandem intramolecular Alder-ene cyclization, proceeds with remote diastereocontrol in the formation of indenes possessing two stereogenic elements (stereocenter and chiral axis). Highly configurationally stable atropisomers have been obtained with dr values up to >98:2. The reaction tolerates a range of commercially available functionalized arylboronic acids and allows the creation of C(sp2)–C(sp2) and C(sp2)–C(sp3) bonds in a single operation. Control experiments suggest that synergetic thermal and Pd-catalyzed cyclizations are likely to be involved in the second elementary step.

Keywords: Alder-ene; atropisomers; boronic acids; cascade; ene-allenes; indenes; palladium catalysis; remote diastereocontrol

Domains: Chemical Sciences; Organic chemistry

Cyril Borie, Nicolas Vanthuyne, Michèle.P Bertrand, Didier Siri, Malek Nechab. Palladium Tandem Catalysis in the Atropodiastereoselective Synthesis of Indenes Bearing Central and Axial Chirality. ACS Catalysis, 2016, ⟨10.1021/acscatal.5b02867⟩. ⟨hal-01406316⟩