# Organocatalytic Stetter Cyclization of Pentoses for the Synthesis of Polyhydroxylated Cyclopentanone Scaffolds

## TL;DR

This paper presents a new method to create complex cyclopentanone structures from pentose sugars using organocatalysis.

## Contribution

A novel organocatalytic Stetter cyclization method for synthesizing polyhydroxylated cyclopentanone scaffolds from aldopentoses.

## Key findings

- The method introduces an intramolecular Michael acceptor for efficient Stetter cyclization.
- Multiple chiral centers and protected hydroxy groups are formed in the resulting cyclopentanone scaffolds.
- Stereochemical permutations can be easily prepared using commercially available d- and l-pentoses.

## Abstract

An organocatalytic
approach for the carbocyclization
of aldopentoses
is disclosed. After initial activation, with the introduction of the
intramolecular Michael acceptor in the substrate, the NHC-catalyzed
Stetter reaction can be performed, giving rise to cyclopentanone scaffolds
bearing multiple chiral centers and protected hydroxy groups. An optional
controlled one-pot elimination provides the corresponding cyclopentenones
as well. Due to the commercial availability of d- and l-pentoses all possible stereochemical permutations of the products
can be prepared conveniently and affordably.