2026-10-14T06:47:07Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33942907 2026-09-19T15:17:35Z category_1 category_4 category_146 category_12 category_13 category_14 category_21 category_272 category_873 category_46 category_931 portal_63 item_type_3 month_year_09_2026

Chiral Rh Diene NHC Complexes and Their Application in Rh-Catalyzed Cycloisomerization of Enynes Derman Batman (25076305) Manuel Kirchhof (9327182) Severin Haid (20473512) Katrin Gugeler (9327185) Alexander Beck (210720) Wolfgang Frey (1510546) Johanna Osterbrink (6159947) Biprajit Sarkar (1305786) Anna Zens (10832326) Johannes Kästner (1644178) Sabine Laschat (1642789) Biophysics Biochemistry Space Science Cell Biology Genetics Molecular Biology Biotechnology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Immunology Information Systems not elsewhere classified reduced catalyst deactivation rarely employed together key interactions enforced enynes chiral dienes dft calculations identified delivered improved activity chiral diene scaffold catalytic studies showed >- heterocyclic carbenes four cationic analogues >)- ietph ), rh diene catalysts nhc ligand ’ bulkier nhc ligands l1 )( nhc 6 </ sub >)- ietph ligand classes important ligands cationic complex strong dependence stereocontrol originates planar geometry neutral complexes metal catalysis kinetic analysis findings highlight enyne cycloisomerization detailed insight dependent distortions decisive influence catalyzed cycloisomerization asymmetric reactivity anion exchange Chiral dienes and <i>N</i>-heterocyclic carbenes (NHC) are important ligands for transition-metal catalysis. Surprisingly, both ligand classes are rarely employed together in Rh complexes. To get more detailed insight into the interaction between NHC and diene ligand simultaneously coordinated to the same Rh center, a series of eight neutral Rh diene NHC complexes, [Rh(L1)(NHC)Cl] (NHC = ICy, IMes, I^<i>i</i>Pr, IPr, SIPr, IMe, (<i>R</i>)-IEtPh, and (<i>S</i>)-IEtPh), and four cationic analogues, [Rh(L1)(NHC)]X (NHC = ICy, IMes, IPr: X = B(Ar^F)₄; NHC = ICy: X = SbF₆), were synthesized from [Rh(L1)Cl] by three complementary synthetic routes and anion exchange. X-ray crystal structure analyses revealed pronounced NHC-dependent distortions from a square-planar geometry in neutral complexes, whereas cationic species remain comparatively rigid. Catalytic studies showed a strong dependence on the NHC ligand’s identity: while NHC incorporation generally reduced yields and enantioselectivities in asymmetric 1,2- and 1,4-additions, the cationic complex [Rh(L1)(ICy)]SbF₆ delivered improved activity and selectivity in 1,6-enyne cycloisomerization, consistent with reduced catalyst deactivation as confirmed by kinetic analysis. DFT calculations identified that stereocontrol originates from key interactions enforced by the chiral diene scaffold, disrupted by bulkier NHC ligands. These findings highlight the decisive influence of NHC sterics on the structure, stability, and asymmetric reactivity of Rh diene catalysts. 2026-09-19T00:00:00Z Dataset Dataset 10.1021/acs.organomet.6c00275.s002 https://figshare.com/articles/dataset/Chiral_Rh_Diene_NHC_Complexes_and_Their_Application_in_Rh-Catalyzed_Cycloisomerization_of_Enynes/33942907 CC BY-NC 4.0