In order to support our mechanistic hypothesis of preactivation of the allylic diol as a mixed cyclic orthoester, we treated alkenyl vicdiol 5 with trimethyl orthoacetate (Scheme 6A). We could observe in NMR the formation of mixed cyclic orthoester 5. Therefore, we propose the mechanism described in Scheme 5B. The diol moiety 1a reacts with trimethyl orthoacetate to form the intermediate mixed cyclic orthoester I. This mixed orthoester can be activated by the Lewis acid to generate an intermediate carbocation II or III, triggering the cyclization and concomitant ring-opening of the cyclic orthoester, affording the THF ring as well as the allylic acetate moiety. Alternatively, a direct substitution upon activation of I by the Lewis acid could also take place. The lack of stereospecificity in this reaction could be explained by the two possible faces of approach in the case of an antiperiplanar substitution of the nucleophile relative to the leaving group. To conclude, in this manuscript we describe a new method involving sequential dual catalysis for the one-pot double allylic substitution of alkenyl vic-diols. Remarkably, this method allows to introduce two different nucleophiles at will in a regio-and chemoselective manner. The scope of nucleophiles is remarkably broad, and two new C-C, C-N, C-O or C-S bonds can be formed in this one-pot process. Although the first allylic substitution is not stereospecific, the reaction can proceed with good diastereoselectivity in the case of secondary alcohol nucleophiles. This new reactivity paves the way to the quick formation of diverse complex molecular scaffolds. Further studies regarding the reaction mechanism and stereoselectivity will be performed in the future.