Mapping out the key carbon–carbon bond-forming steps in Mn-catalysed C–H functionalization

TY - JOUR

T1 - Mapping out the key carbon–carbon bond-forming steps in Mn-catalysed C–H functionalization

AU - Hammarback, Lars Anders

AU - Clark, Ian P.

AU - Sazanovich, Igor

AU - Towrie, Michael

AU - Robinson, Alan

AU - Clarke, Francis

AU - Meyer, Stephanie

AU - Fairlamb, Ian James Stewart

AU - Lynam, Jason Martin

N1 - © 2018 Springer Nature Limited. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2018/11/1

Y1 - 2018/11/1

N2 - Detailed understanding of the mechanistic processes that underpin transition metal-catalysed reactions allows for the rational and de novo development of complexes with enhanced activity, efficacy and wider substrate scope. Directly observing bond cleaving and forming events underpinning a catalytic reaction is non-trivial as the species that facilitate these steps are frequently short-lived and present at low concentrations. Here we describe how the photochemical activation of a manganese precatalyst, [Mn(ppy)(CO)4], results in selective loss of a carbonyl ligand simulating entry into the catalytic cycle for Mn-promoted C–H bond functionalisation. Time-resolved infra-red spectroscopy (ps-ms timescale) allows direct observation of the species responsible for the essential carbon-carbon bond formation step and an evaluation of the factors affecting its rate. The mechanistic information prompted discovery of a new photochemically initiated manganese-promoted coupling of phenylacetylene with 2-phenylpyrindine. This study provides unique insight into the mechanistic pathways which underpin catalysis by an Earth-abundant metal, manganese.

AB - Detailed understanding of the mechanistic processes that underpin transition metal-catalysed reactions allows for the rational and de novo development of complexes with enhanced activity, efficacy and wider substrate scope. Directly observing bond cleaving and forming events underpinning a catalytic reaction is non-trivial as the species that facilitate these steps are frequently short-lived and present at low concentrations. Here we describe how the photochemical activation of a manganese precatalyst, [Mn(ppy)(CO)4], results in selective loss of a carbonyl ligand simulating entry into the catalytic cycle for Mn-promoted C–H bond functionalisation. Time-resolved infra-red spectroscopy (ps-ms timescale) allows direct observation of the species responsible for the essential carbon-carbon bond formation step and an evaluation of the factors affecting its rate. The mechanistic information prompted discovery of a new photochemically initiated manganese-promoted coupling of phenylacetylene with 2-phenylpyrindine. This study provides unique insight into the mechanistic pathways which underpin catalysis by an Earth-abundant metal, manganese.

UR - http://www.scopus.com/inward/record.url?scp=85054588126&partnerID=8YFLogxK

U2 - 10.1038/s41929-018-0145-y

DO - 10.1038/s41929-018-0145-y

M3 - Article

SN - 2520-1158

VL - 1

SP - 830

EP - 840

JO - Nature Catalysis

JF - Nature Catalysis

IS - 11

ER -