# Deuterated Cyclopropanation of Alkenes by Iron Catalysis

## TL;DR

A new iron-catalyzed method allows easy synthesis of deuterated cyclopropanes, useful for drug development and metabolism studies.

## Contribution

A mild, practical, and diazo-free iron-catalyzed method for deuterated cyclopropanation of alkenes is introduced.

## Key findings

- The method uses dichloromethane-d2 to achieve high deuterium incorporation in cyclopropanes.
- A wide range of alkenes with different functional groups is compatible with the deuterated cyclopropanation.
- The method is highly tolerant to air and water, making it practical for use in pharmaceutical applications.

## Abstract

Deuterium labeling is a key tool used in drug development
to observe
and prevent metabolism. Here, we report a mild and operationally simple
protocol for the synthesis of deuterated cyclopropanes with high levels
of deuterium incorporation. This Fe-catalyzed strategy uses dichloromethane-d
2 for safe, practical, and diazo-free access
to carbene reactivity. A sterically and electronically diverse range
of alkenes with varying functional groups are tolerated in this deuterated
cyclopropanation. This highly air and water tolerant method complements
existing strategies and significantly broadens access to valuable
deuterated cyclopropanes, including with applications for the late-stage
functionalization of pharmaceuticals.