Dataset for: "Does the configuration at metal matter in Noyori-Ikariya type asymmetric transfer hydrogenation catalysts?"
Noyori-Ikariya
type [(arene)RuCl(TsDPEN)] complexes are widely used C=O and C=N reduction catalysts
which produce chiral alcohols and amines via a key ruthenium-hydride
intermediate that determines the stereochemistry of the product. Whereas many
details about the interactions of the pro-chiral substrate with the hydride
complex, and the nature of the hydrogen transfer from the latter to the former
have been investigated over the past 25 years, the role of the stereochemical
configuration at the stereogenic ruthenium centre in the catalysis has not been
elucidated so far. Using operando FlowNMR spectroscopy and Nuclear Overhauser
Effect spectroscopy we show the existence of two diastereomeric hydride
complexes under reaction conditions, assign their absolute configurations in
solution, and monitor their interconversion during transfer hydrogenation
catalysis. Configurational analysis and multi-functional DFT calculations show
the λ-(R,R)S configured [(mesitylene)RuH(TsDPEN)] complex to be both
thermodynamically and kinetically favoured over its λ-(R,R)R isomer with the opposite
configuration at ruthenium. Computational analysis of both diastereomeric catalytic
manifolds show the major λ-(R,R)S configured [(mesitylene)RuH(TsDPEN)] complex
to dominate asymmetric ketone reduction catalysis, with the minor λ-(R,R)R
[(mesitylene)RuH(TsDPEN)] stereoisomer being both less active and less
enantioselective. These findings also hold true for a tethered catalyst derivative
with a propyl linker between the arene and TsDPEN ligands, and thus show
enantioselective transfer hydrogenation catalysis with Noyori-Ikariya complexes
to proceed via a lock-and-key mechanism.
Funding
Y0603
EPSRC Centre for Doctoral Training in Sustainable Chemical Technologies
Engineering and Physical Sciences Research Council
Find out more...An integrated, multi-dimensional in-operando Reaction Monitoring Facility for Homogeneous Catalysis Research
Engineering and Physical Sciences Research Council
Find out more...