A phosphine-catalyzed reaction of an allenoate with aldehydes furnished (2, 6-diaryl-[1, 3] dioxan-4-ylidene)-acetates 4 in excellent to moderate yields with complete diastereoselectivity and high E/Z-selectivities. Upon removal of the acetal functionality in this domino reaction product 4, δ-hydroxy-β-ketoester 11 was obtained. The reported vinylphosphonium-based approach provides a new way to achieve a synthesis of δ- ...