# Sustainable Photocatalytic Synthesis of Glitazones via Riboflavin Tetraacetate

## TL;DR

A new sustainable method uses light and a vitamin derivative to make antidiabetic drugs more efficiently.

## Contribution

A novel photocatalytic method for synthesizing glitazones without transition metals is introduced.

## Key findings

- The method uses riboflavin tetraacetate to catalyze the coupling of thiazolidinediones with radical precursors.
- The process is transition-metal-free and works under mild conditions with various functional groups.
- The protocol was successfully used to prepare pioglitazone in three steps.

## Abstract

A more sustainable
and versatile method to access antidiabetic
glitazones is demanded. Herein, we report the unprecedented photocatalytic
coupling of N-protected methylene thiazolidinediones
with radical precursors (organoborates or carboxylic acids) under
riboflavin tetraacetate catalysis. The methodology accepts various
functional groups and affords (Het)­Ar-(CH2)n-thiazolidinediones by transition-metal-free organic photoredox catalysis
under mild conditions. The applicability of the developed protocol
is showcased by the three-step preparation of the antidiabetic pioglitazone
drug.