Crossed Regio‐ and Enantioselective Iron‐Catalyzed [4+2]‐Cycloadditions of Unactivated Dienes

Autor: Elena Braconi, Nicolai Cramer
Rok vydání: 2021
Předmět:
Zdroj: Angewandte Chemie International Edition. 61
ISSN: 1521-3773
1433-7851
DOI: 10.1002/anie.202112148
Popis: The cyclohexene motif is ubiquitous in nature and specialty chemicals. A straightforward selective access to chiral cyclohexenes from unactivated dienes and dienophiles is not feasible by classical Diels-Alder reaction and constitutes an unsolved synthetic challenge. We report a mild and enantioselective iron-catalyzed cross-[4+2]-cycloaddition of unactivated dienes providing access to chiral 1,3-substituted vinyl-cyclohexenes. The development of bis -dihydroisoquinoline ligands was vital to obtain iron complexes that display high reactivities and excellent chemo-, regio- and enantioselectivities towards the targeted cyclohexenes. A range of diene substrates is well accommodated including feedstocks like butadiene, isoprene and myrcene. The structures of different iron complexes are mapped by X-ray crystallographic analysis and linked to their performance.
Databáze: OpenAIRE