Synthesis of an M + 7 stable isotope of γ‐cyhalothrin

γ‐Cyhalothrin is a single isomer, synthetic pyrethroid insecticide. This material was originally developed and marketed by Pytech Chemicals, a joint venture between Dow AgroSciences and Cheminova A/S. Cheminova A/S now wholly owns Pytech Chemical. As a part of registration studies, there was a need for a stable isotope of γ‐cyhalothrin to serve as an internal standard. This paper will discuss the 11‐step synthesis that was used to prepare an M + 7 stable isotope of γ‐cyhalothrin by utilizing triethyl phosphonoacetate‐d₂ and acetone‐d₆ to incorporate deuterium into the molecule. In the end, the diastereomers were separated by preparative reverse‐phase HPLC to give γ‐cyhalothrin‐d₇ in an overall yield of 6%. Copyright © 2012 John Wiley & Sons, Ltd.