Mechanism and Regioselectivity of Rh(III)-Catalyzed Intermolecular Annulation of Aryl-Substituted Diazenecarboxylates and Alkenes: DFT Insights

Handle URI:
http://hdl.handle.net/10754/621701
Title:
Mechanism and Regioselectivity of Rh(III)-Catalyzed Intermolecular Annulation of Aryl-Substituted Diazenecarboxylates and Alkenes: DFT Insights
Authors:
Ajitha, Manjaly John; Huang, Kuo-Wei ( 0000-0003-1900-2658 )
Abstract:
The mechanism of Rh-catalyzed intermolecular annulation of aryl-substituted diazenecarboxylates and alkenes was investigated using density functional theory (DFT) (PCM-M062X/6-311+G(d,p)//M062X/6-31G(d)). The acetate ligand (OAc)-assisted C-H activation via the formation of a five-membered rhodacycle (I-TS1; ΔG‡ = 19.4 kcal/mol) is more favorable compared to that via a four-membered intermediate (II-TS1; ΔG‡ = 27.8 kcal/mol). Our results also revealed that the seven-membered intermediate (I-3, ΔGrel = -6.8 kcal/mol) formed after the alkene insertion could undergo a coordination switch with the adjacent nitrogen atom (via TScs; ΔG‡ = 16.5 kcal/mol) to produce a thermodynamically stable six-membered intermediate (II-3, ΔGrel = -10.4 kcal/mol), eventually leading to a cyclization process followed by a barrierless ligand-assisted protonation to yield the final product. The β-hydride elimination product was found to be kinetically and thermodynamically undesirable. The rate-determining step is identified as the initial C-H activation, consistent with the previous kinetic studies. Notably, DFT studies offered important insights on the ability of the substrate (diazene carboxylate) to promote the switchable coordination site selectivity during the reaction to achieve a lower energy pathway. © 2016 American Chemical Society.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division
Citation:
Ajitha MJ, Huang K-W (2016) Mechanism and Regioselectivity of Rh(III)-Catalyzed Intermolecular Annulation of Aryl-Substituted Diazenecarboxylates and Alkenes: DFT Insights. Organometallics 35: 450–455. Available: http://dx.doi.org/10.1021/acs.organomet.5b00831.
Publisher:
American Chemical Society (ACS)
Journal:
Organometallics
Issue Date:
5-Feb-2016
DOI:
10.1021/acs.organomet.5b00831
Type:
Article
ISSN:
0276-7333; 1520-6041
Sponsors:
Financial support is provided by King Abdullah University of Science and Technology.
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/acs.organomet.5b00831
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorAjitha, Manjaly Johnen
dc.contributor.authorHuang, Kuo-Weien
dc.date.accessioned2016-11-03T13:23:04Z-
dc.date.available2016-11-03T13:23:04Z-
dc.date.issued2016-02-05en
dc.identifier.citationAjitha MJ, Huang K-W (2016) Mechanism and Regioselectivity of Rh(III)-Catalyzed Intermolecular Annulation of Aryl-Substituted Diazenecarboxylates and Alkenes: DFT Insights. Organometallics 35: 450–455. Available: http://dx.doi.org/10.1021/acs.organomet.5b00831.en
dc.identifier.issn0276-7333en
dc.identifier.issn1520-6041en
dc.identifier.doi10.1021/acs.organomet.5b00831en
dc.identifier.urihttp://hdl.handle.net/10754/621701-
dc.description.abstractThe mechanism of Rh-catalyzed intermolecular annulation of aryl-substituted diazenecarboxylates and alkenes was investigated using density functional theory (DFT) (PCM-M062X/6-311+G(d,p)//M062X/6-31G(d)). The acetate ligand (OAc)-assisted C-H activation via the formation of a five-membered rhodacycle (I-TS1; ΔG‡ = 19.4 kcal/mol) is more favorable compared to that via a four-membered intermediate (II-TS1; ΔG‡ = 27.8 kcal/mol). Our results also revealed that the seven-membered intermediate (I-3, ΔGrel = -6.8 kcal/mol) formed after the alkene insertion could undergo a coordination switch with the adjacent nitrogen atom (via TScs; ΔG‡ = 16.5 kcal/mol) to produce a thermodynamically stable six-membered intermediate (II-3, ΔGrel = -10.4 kcal/mol), eventually leading to a cyclization process followed by a barrierless ligand-assisted protonation to yield the final product. The β-hydride elimination product was found to be kinetically and thermodynamically undesirable. The rate-determining step is identified as the initial C-H activation, consistent with the previous kinetic studies. Notably, DFT studies offered important insights on the ability of the substrate (diazene carboxylate) to promote the switchable coordination site selectivity during the reaction to achieve a lower energy pathway. © 2016 American Chemical Society.en
dc.description.sponsorshipFinancial support is provided by King Abdullah University of Science and Technology.en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/acs.organomet.5b00831en
dc.titleMechanism and Regioselectivity of Rh(III)-Catalyzed Intermolecular Annulation of Aryl-Substituted Diazenecarboxylates and Alkenes: DFT Insightsen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalOrganometallicsen
kaust.authorAjitha, Manjaly Johnen
kaust.authorHuang, Kuo-Weien
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.