Open Access Article
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Expression of concern: Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates
Kehuan Sunac,
Cheng Taobcd,
Bohua Long*cd,
Xiaobin Zeng*e,
Zhengzhi Wu*cd and
Ronghua Zhang*a
aCollege of Traditional Chinese Medicine, Jinan University, Guangzhou 510632, China
bIntegrated Chinese and Western Medicine Postdoctoral Research Station, Jinan University, Guangzhou 510632, China
cThe First Affiliated Hospital of Shenzhen University, Shenzhen 518035, China. E-mail: bhlong121@163.com
dShenzhen Institute of Geriatric Medicine, Shenzhen, China
eCentral Center Lab of Longhua Branch, Department of Infectious Disease, Shenzhen People's Hospital, 2nd Clinical Medical College of Jinan University, Shenzhen 518120, Guangdong Province, China
First published on 7th July 2023
Abstract
Expression of concern for ‘Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates’ by Kehuan Sun et al., RSC Adv., 2019, 9, 32017–32020, https://doi.org/10.1039/C9RA06827A.
The Royal Society of Chemistry is publishing this expression of concern in order to alert readers that concerns have been raised regarding the integrity of the NMR data in the ESI.
Several impurity peaks have been removed from the NMR spectra. The authors have provided the original raw data, however, an independent expert has stated it would not be appropriate to re-publish the original spectra and requested the authors reproduce their results.
An expression of concern will continue to be associated with the article until we receive conclusive evidence regarding the reliability of the reported data.
Laura Fisher
30th June 2023
Executive Editor, RSC Advances
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