AbstractAn efficient organocatalytic method for the asymmetric preparation of benzopyran- and benzofuran-fused polycyclic acetals is described for the first time. This useful approach includes an interesting tunable Michael–acetalization of nitrostyrenes or α-aromatization–acetalization of quinones. Under mild conditions, simple cyclic hemiacetals could be stereoselectively converted into four different types of polyheterocycles that serve as scaffolds for a number of bioactive natural products.

A novel method for organocatalytic oxidation through oxidative enamine catalysis was developed with excellent compatibility for the direct syntheses of enals from simple saturated alcohols. By using this amine-catalyzed IBX-oxidation, a wide range of aromatic and aliphatic substituted enals were successfully generated in high yields and exclusively stereoselective E-geometry. Moreover, varying the solvents and/or the loading amounts of IBX allowed for the selective oxidation of alcohols and aldehydes. Importantly, the homologous application of this method provided a selective and efficient way of preparing various highly sensitive conjugated polyene frameworks, which are enriched in natural products.

•A silver catalyzed cyclization of acetylene amine was developed to synthesize 4,6-substituted pyrrolo[3,2-d]pyrimidine.•The method was found to be compatible with wide chemical functionalities in excellent yields.•The target molecules, pyrrolo[3,2-d]pyrimidine, have wide bioactivities, currently studied in our laboratory.A silver catalyzed cyclization of acetylene amine was developed to synthesize 4,6-substituted pyrrolo[3,2-d]pyrimidine, a bioactive isosteric scaffold of purine. Starting from simple commercially available acetylenes and pyrimidines, the method was found to be compatible with wide chemical functionalities, leading to a series of pyrrolo[3,2-d]pyrimidines in 84–91% yields.

An efficient aminocatalytic enantioselective Michael addition of readily available cyclic hemiacetals to nitroolefins has been developed. The strategy serves as a powerful approach to synthetically valuable chiral 3-substituted tetrahydrofurans (THFs) and tetrahydropyrans (THPs). The synthetic utilities of the versatile Michael adducts also have been demonstrated in the synthesis of 2,3-disubstituted cyclic ethers, α-substituted lactones and venlafaxine analogues.

A cascade method that includes nucleophilic aromatic substitution and Smiles rearrangement reaction has been developed. The method shows good functional group tolerance with different electronic properties, providing efficient and practical access to dibenzoxazepinone architecture. Comparison of the products from cascade and step-by-step protocols demonstrates Smiles rearrangement is the pivotal step in the formation of heterocyclic products.

An organocatalytic aldol reaction of cyclic hemiacetals to aldehydes was developed. As a seldom reported nucleophile in organocatalysis, cyclic hemiacetals herein provided a smooth method to approach a series of cyclic ether substrates with excellent ee value, good yields, and good to moderate diastereoselectivity. The absolute configuration and relative configuration were determined by a Mosher method and 2D NMR spectral analysis of the derivative, respectively.

An efficient aminocatalytic enantioselective Michael addition of readily available cyclic hemiacetals to nitroolefins has been developed. The strategy serves as a powerful approach to synthetically valuable chiral 3-substituted tetrahydrofurans (THFs) and tetrahydropyrans (THPs). The synthetic utilities of the versatile Michael adducts also have been demonstrated in the synthesis of 2,3-disubstituted cyclic ethers, α-substituted lactones and venlafaxine analogues.

A novel method for organocatalytic oxidation through oxidative enamine catalysis was developed with excellent compatibility for the direct syntheses of enals from simple saturated alcohols. By using this amine-catalyzed IBX-oxidation, a wide range of aromatic and aliphatic substituted enals were successfully generated in high yields and exclusively stereoselective E-geometry. Moreover, varying the solvents and/or the loading amounts of IBX allowed for the selective oxidation of alcohols and aldehydes. Importantly, the homologous application of this method provided a selective and efficient way of preparing various highly sensitive conjugated polyene frameworks, which are enriched in natural products.