# Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

## TL;DR

This paper presents a new three-step chemical method to modify β-ketosulfones using a benzoyl group to create new amine compounds.

## Contribution

A novel three-step method for dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines is introduced.

## Key findings

- The primary domino reaction yields 3-sulfonyl-3-benzoylpyrrolidines in good to high yields.
- The retro-Claisen reaction and Michael addition produce novel 4-Nu-3-sulfonylbutan-1-amines in moderate to excellent yields.
- Reduction with LiAlH4 successfully substitutes the nucleophilic group with hydrogen in good yields.

## Abstract

Herein, a three-step method for the simultaneous dialkylaminoethylation and heteromethylation of active methylene β-ketosulfones, promoted by a leaving benzoyl group, is proposed. The primary domino reaction of sarcosine, paraformaldehyde, and β-ketosulfones affords 3-sulfonyl-3-benzoylpyrrolidines in good to high yields. Further treatment with alkyl halides and heating of the quaternary ammonium salt in the presence of a O-, S- or N-nucleophile with cesium carbonate leads to a retro-Claisen reaction, ring-opening and Michael addition. The resulting novel 4-Nu-3-sulfonylbutan-1-amines are isolated in moderate to excellent overall yields. The reduction of the obtained products with LiAlH4 leads to a substitution of the attached nucleophilic moiety with hydrogen in good yields.