Facile Synthesis of (Z,E)-9,11-Hexadecadienal, the Major Sex Pheromone Component of the Sugarcane Borer Diatraea saccharalis: An Efficient Strategy for Synthesis of (Z,E)-Dienic Pheromones

Abstract

Practical and improved procedures for the synthesis of 7-bromo-(Z,E)-4,6-heptadienal by Pd(II)-catalyzed coupling reaction were developed. Based on the improved method, an efficient and stereoselective synthesis of (Z,E)-9,11-hexadecadienal, the main pheromone component of the sugarcane borer, Diatraea saccharalis, was achieved in 38% overall yield, which more desirable then previously reported methods. The stereochemistry relied on cross-coupling between Grignard reagent and protected 7-bromo-(Z,E)-4,6-heptadienal. The concise and facile synthetic strategy described herein provided a generally synthetic approach to other (Z,E)-dienic compounds.

GRAPHICAL ABSTRACT

Keywords:

• 7-Bromo-(Z,E)-4,6-heptadienal
• Kumada cross-coupling
• pheromone synthesis
• sugarcane borer
• (Z,E)-9,11-hexadecadienal

ACKNOWLEDGMENT

We gratefully acknowledge the State Key Laboratory of Elemento-organic Chemistry, Nankai University (Grant No. 0703), for financial support.

Notes

^a Pd(OAc)₂ (1 mmol), halides (0.6 mol), and electron-deficient alkenes (0.5 mol), solvent (120 mL, HOAc/H₂O 5:1,v/v), <15 °C.