# Correction and Removal of Expression of Concern: Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates

## TL;DR

This paper corrects and removes a concern about a method for synthesizing specific chemical compounds.

## Contribution

The paper addresses and resolves an issue with a previously published synthetic chemistry method.

## Key findings

- A correction was issued for the original paper's content.
- The Expression of Concern was removed following resolution of the issue.

## Abstract

Correction and Removal of 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, DOI: https://doi.org/10.1039/C9RA06827A.