Correction: Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones

Abstract

Correction for ‘Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones’ by Feng Yin et al., Org. Biomol. Chem., 2017, 15, 6089–6092.

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The authors have discovered errors in the assignment of the relative configuration and absolute configuration of 3 shown in Schemes 3 and 4, obtained from 2g and 2h, respectively, which were synthesized using catalyst F. The correct structure of 3, (3S,5R)-5-methylpyrrolidine-3-carboxylic acid, is indicated below. The correct structure was determined by the X-ray crystal structural analysis of a derivative of 3, which will be reported separately in the future.

Because 3 is the cis-isomer, the sentence “Note that 3 was previously synthesized from 4-hydroxy-proline via more than 10 steps.” in the original article is corrected to: “Note that the trans-isomer of 3 was previously synthesized from 4-hydroxy-proline via more than 10 steps.”

Because the absolute configurations of 2a, 2g, 2h, and 5 were deduced from 3, these compounds, obtained from the reactions using catalyst F, are also corrected as indicated below.

Accordingly, the plausible transition state shown in Scheme 3 is corrected as indicated below.

Because absolute configurations of 2b, 2c, 2d, 2e, 2f, 2i, 2j, and 2k were also determined by analogy, these compounds, obtained from the reactions using catalyst F, are also corrected as indicated below. By analogy, 10 is also corrected as indicated below. Relative stereochemistries of 9a and 9b remain unaffected.

The authors noticed that in 5-membered ring systems, NOE signals in NOESY spectra can be observed between a proton attached to a carbon on the 5-membered ring and a substituent at the second carbon from the proton-attached carbon on the same ring, even when they are in the trans relationship.

The original ESI was replaced by a correspondingly revised version on 11th April 2018.

The authors apologize for these errors and for any inconvenience caused. The conclusions of the article are not affected by the corrections described here.

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

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