Phosphoramidite-based photoresponsive ligands displaying multifold transfer of chirality in dynamic enantioselective metal catalysis

The transfer and amplification of chirality in biological and artificial systems is a fundamental process that allows for a dynamic control of structure and function. Only a few responsive

systems harness the dynamic transfer of chirality and can act as photoswitchable chiral inductors. Here we demonstrate that photoresponsive phosphoramidite ligands based on a chiral

biaryl-substituted molecular switch can be used to alter the activity and invert the stereoselectivity of a copper-catalysed asymmetric conjugate addition. The phosphoramidites were obtained

as pairs of diastereoisomers, each displaying a distinct catalytic activity and stereoselectivity as a result of the light-controlled matched–mismatched interaction between the fixed

chirality at the phosphorus atom and the dynamic chirality of the switch. The result is an elegant balance of two competing catalysts, of which the complementary catalytic performance is

tunable via light, which takes advantage of the internal dynamic transfer of chirality on reversible alkene photoisomerization. This discovery paves the way for the future development of

more complex chirality-dependent photoresponsive and multitasking catalysts.

All the data generated or analysed during this study are included in this article (and its Supplementary Information files). Crystallographic data for the structure L1 reported has been

deposited at the Cambridge Crystallographic Data Centre (CCDC) under the deposition number 1990520. This data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif.

This work was supported financially by the Netherlands Organization for Scientific Research (NWO-CW), Foundation for Fundamental Research on Matter (FOM, a subsidiary of NWO), the Zernike

Institute for Advanced Materials, The Royal Netherlands Academy of Arts and Sciences (KNAW), The European Research Council (Advanced Investigator Grant no. 694345 to B.L.F.), Ministry of

Education, Culture and Science (Gravitation program 024.001.035) and the University of Groningen. The authors thank E. Otten for the X-ray structure experiments.

These authors contributed equally: Stefano F. Pizzolato and Peter Štacko.

Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, AG

Groningen, the Netherlands

Stefano F. Pizzolato, Peter Štacko, Jos C. M. Kistemaker, Thomas van Leeuwen & Ben L. Feringa

S.F.P., P.S., J.C.M.K. and B.L.F. conceived the project. S.F.P. and P.S. carried out the experimental work. J.C.M.K. and T.v.L. conducted the computational study. All the authors contributed

to the design of the experiments, the analysis of the data and the writing of the paper.

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