Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene. Issue 40 (9th September 2020)

• Record Type: Journal Article
• Authors: Thadkapally, Srinivas; Farshadfar, Kaveh; Drew, Melanie A.; Richardson, Christopher; Ariafard, Alireza; Pyne, Stephen G.; Hyland, Christopher J. T.
• Is Part Of: Chemical science. Volume 11:Issue 40(2020)
• Page Start: 10945
• Page End: 10950
• Publication Date: 2020-09-09
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc04390g
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Room temperature Rh-catalysed tetradehydro-Diels–Alder reaction via an unusual Rh-stabilised allene. Abstract : Efficient methods for the synthesis of fused-aromatic rings is a critical endeavour in the creation of new pharmaceuticals and materials. A direct method for preparing these systems is the tetradehydro-Diels–Alder reaction, however this is limited by the need for harsh reaction conditions. A potential, but underdeveloped, route to these systems is via transition metal-catalysed cycloaromatisation of ene-diynes. Herein, tethered unconjugated enediynes have been shown to undergo a facile room-temperature Rh I -catalysed intramolecular tetradehydro-Diels–Alder reaction to produce highly substituted isobenzofurans, isoindolines and an indane. Furthermore, experimental and computational studies suggest a novel mechanism involving an unprecedented and complex Rh I /Rh III /Rh I /Rh III redox cycle involving the formation of an unusual strained 7-membered rhodacyclic allene intermediate and a Rh III -stabilized 6-membered ring allene complex.