Rhodium-catalysed tetradehydro-Diels-Alder reactions of enediynes: Via a rhodium-stabilized cyclic allene

Authors

Srinivas Thadkapally, University of WollongongFollow
Kaveh Farshadfar
Melanie A. DrewFollow
Christopher Richardson, University of WollongongFollow
Alireza AriafardFollow
Stephen G. Pyne, University of WollongongFollow
Christopher J. T Hyland, University of WollongongFollow

RIS ID

146359

Publication Details

Thadkapally, S., Farshadfar, K., Drew, M., Richardson, C., Ariafard, A., Pyne, S. & Hyland, C. (2020). Rhodium-catalysed tetradehydro-Diels-Alder reactions of enediynes: Via a rhodium-stabilized cyclic allene. Chemical Science, 11 (40), 10945-10950.

Abstract

The Royal Society of Chemistry. 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 RhI-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 RhI/RhIII/RhI/RhIII redox cycle involving the formation of an unusual strained 7-membered rhodacyclic allene intermediate and a RhIII-stabilized 6-membered ring allene complex.