# O‑Thien-2-yl Esters: A Synthetic Approach to a Rare Class of Materials Using a Modified Steglich Esterification

## TL;DR

A modified Steglich esterification method is developed to efficiently synthesize O-thien-2-yl esters, avoiding unwanted byproducts.

## Contribution

A modified Steglich esterification method is introduced to synthesize O-thien-2-yl esters with high yields.

## Key findings

- Standard Steglich conditions led to low yields due to O–N acyl migration forming N-acylurea.
- Adding p-TSA·H2O eliminated N-acylurea formation and improved yields to 51–85%.
- Various O-thien-2-yl esters were successfully synthesized using the modified method.

## Abstract

Herein, we describe a simple procedure for the transformation
of
3-thien-2-one to O-thien-2-yl esters via modified
Steglich esterification. Attempted esterification using standard Steglich
conditions gave low yields due to a competing O–N acyl migration,
resulting in the formation of N-acylurea as the major
product. The addition of a catalytic amount of p-TSA·H2O eliminates the formation of the N-acylurea.
Various O-thien-2-yl esters have been synthesized
using this procedure in yields of 51–85%.