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ChoRetraction2FHA_ChemRxiv.pdf (70.23 kB)

Site-selective enzymatic C‒H amidation for synthesis of diverse lactams

revised on 03.01.2020, 22:10 and posted on 03.01.2020, 22:15 by Inha Cho, Zhijun Jia, Frances H. Arnold

Please note that this work has been retracted by the authors.

After publication of the Report “Site-selective enzymatic C‒H amidation for synthesis of diverse lactams” in Science (1, also linked in metadata), efforts to reproduce the work showed that the enzymes do not catalyze the reactions with the activities and selectivities claimed. Careful examination of the first author’s lab notebook then revealed missing contemporaneous entries and raw data for key experiments. The authors therefore have retracted the article from Science and are now retracting the preprint from ChemRxiv. The original paper can be accessed by selecting “Version 1” of the preprint below, or by accessing

Inha Cho, Zhi-Jun Jia, Frances H. Arnold*

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.

*Corresponding author. Email:


1. I. Cho, Z.-J. Jia, F. H. Arnold, Science 364, 575 (2019). DOI: 10.1126/science.aaw9068


Directed evolution of cytochrome P450 enzymes fine-tunes site selectivity of new-to-nature C‒H amidation for modular, sustainable and scalable preparation of enantio-enriched β-, γ- and δ-lactams.


Email Address of Submitting Author


California Institute of Technology



ORCID For Submitting Author


Declaration of Conflict of Interest

Caltech has filed a provisional patent application (CIT-8187-P)