Calcium-catalyzed dehydrative allylation of P-ylides and sequential Wittig reaction for streamlined access to versatile 1,4-dienes

A transition metal-free dehydrative allylation of stabilized P-ylides with activated allylic alcohols has been developed. This protocol utilizes a calcium catalyst to facilitate the cleavage of C-OH bonds and enables smooth dehydrative cross-coupling with P-ylides, resulting in water as the sole by-product. Remarkably, this transformation exhibits excellent tolerance towards a diverse range of allylic alcohols and P-ylides. Furthermore, the subsequent Wittig reaction affords a wide array of highly functionalized 1,4-dienes with high yields.