We report herein a gold and palladium sequential catalysis system to access furan-fused nine-membered heterocycles in high efficiency and enantioselectivity. In this one-pot procedure, easily accessible enynamides undergo cyclization to generate azadienes in situ that participate in enantioselective formal [5+4] cycloaddition with vinyl ethylene carbonates. Conformation-controlled highly diastereoselective derivatizations of these medium-sized rings, coupled with oxidative furan cleavage, have enabled the access to diverse densely-functionalized nine-membered lactams.Medium-sized heterocycles (8 to 11-membered rings) are important structural motifs in various bioactive natural products. [1] The synthesis of these medium-sized rings, however, still remains a great challenge for catalytic method development. Out of the different synthetic strategies developed for medium-sized ring formation, intramolecular cyclization or ring expansion is most explored. [2,3] As an alternative and synthetically flexible approach, intermolecular dipolar cycloaddition provides a significant advantage of directly coupling two building blocks (serving as dipoles and dipolarophiles) to produce medium-sized heterocycles. [4] However, success along these lines remains limited, with cycloaddition of only a few classes of 1,4-dipolarophiles reported in the literature. Our group has introduced a dihydrobenzofuran-derived azadiene [5] to realize highly stereoselective Pd-catalyzed cycloadditions for the preparation of nine-or ten-membered benzofuran/indole-fused heterocycles. [5b-d] The same substrate was also used by the Lu group to achieve phosphine-catalyzed enantioselective eight-membered heterocycle synthesis. [6] The Shibata group has introduced CF 3 -substituted benzooxazinones for Pd-catalyzed decarboxylative cycloaddition to access benzo-fused nine-or twelve-membered heterocycles. [7] The formal [5+4] cycloaddition using ortho-quinone methides to access enantioenriched benzo-fused nine-membered rings have also been reported by the Fan group and the Guo group. [8] Despite these advances, it is important to note that due to the special Scheme 1. Diverse nine-membered heterocycles prepared from in situ generated azadienes.