One-pot synthesis yields grapevine moth sex pheromone

The European grapevine moth (Lobesia botrana) spoils vineyard fruit across the globe. One of the most effective weapons against the pest is the moth’s own sex pheromone. When sprayed into the air around vineyards, it leads male moths on a fruitless chase to find females and disrupts mating. Although eco-friendly, the pheromone, (7E,9Z)-dodecadien-1-yl acetate, is about 60% more expensive than traditional pesticides. The standard synthetic route starts with a pricey eight-carbon alkyne and requires isolating four intermediates. Now, Gérard Cahiez of Chimie ParisTech, Olivier Guerret of M2i Life Sciences, and colleagues have come up with a less costly, one-pot synthesis and report making the pheromone on a 50-kg industrial scale (Org. Process Res. Dev. 2017, DOI: 10.1021/acs.oprd.7b00206). The new—and simpler—synthesis is based on a cross-coupling reaction between a dienol phosphate and a Grignard reagent that uses an iron-based catalyst instead of a more expensive palladium catalyst. The route starts with a cheaper six-carbon alcohol, proceeds in one reactor, and has an 85% yield, compared with an 11% yield for the original process. The researchers are working on a microencapsulated formulation that gradually releases the pheromone when sprayed on grapevines and should cost the same as conventional pesticides, Guerret says.