Axially chiral compounds are widespread in biologically active compounds and are useful chiral ligands or organocatalysts in asymmetric catalysis. It is well-known that styrenes are one of the most abundant and principal feedstocks and thus represent excellent prospective building blocks for chemical synthesis. Driven by the development of atroposelective synthesis of axially chiral styrene derivatives, we discovered herein the asymmetric organocatalytic approach via direct Michael addition reaction of substituted diones/ketone esters/malononitrile to alkynals. The axially chiral styrene compounds were produced with good chemical yields, enantioselectivities and almost complete E/Z-selectivities through a secondary amine-catalysed iminium activation strategy under mild conditions. Such structural motifs are important precursors for further transformations into biologically active compounds and synthetic useful intermediates and may have potential applications in asymmetric synthesis as olefin ligands or organocatalysts.

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An organocatalytic atroposelective strategy for accessing enantioenriched axially chiral IAN analogues was developed for the first time. A class of novel atropisomeric C2arylquinoline skeletons were synthesized with high enantiocontrol via chiral phosphoric-acid-catalyzed heteroannulation of in situ generated vinylidene ortho-quinone methide (VQM) intermediates with ortho-aminophenones. The strategy tolerated a broad substrate scope, providing a facile organocatalytic approach to IAN analogues in good yields and excellent enantioselectivities under mild reaction conditions. Moreover, the synthetic utility of this methodology was illustrated through further transformations into IAN-type ligand and axially chiral thiourea. Research on axially chiral biaryls has developed rapidly and gained considerable momentum in recent years because of their widespread appearance in natural products, [1] bioactive molecules, [2] and privileged chiral ligands and catalysts. [3] In sharp contrast, the asymmetric construction of axially chiral heterobiaryls was still underdeveloped, [4] even though it is scientifically important and of great significance in practical application. [5] For instance, the effective approaches to access axially chiral 2-arylpyridines (isoquinolines) are especially scanty, while they have emerged as essential backbone of numerous chiral catalysts and ligands in asymmetric catalysis (Figure 1). [6] This type of heteroaryl atropisomers ordinarily formed a chelate ring with metal atom through the coordination of nitrogen and other donor atoms, such as phosphorus, nitrogen, oxygen, and sulfur, providing the asymmetric induction in various metal-catalyzed enantioselective transformations (Figure 2 a). [7] Conventionally, synthetic approaches for enantioenriched 2-arylpyridine/isoquinoline skeletons depend mainly on transition-metal mediated patterns, such as cross-coupling, [6i,r] (dynamic) kinetic resolution/ transformation, [6a,g,h,j-q,s] and de novo construction of a (hetero)aromatic ring.

The first utility of praseodymium as a mediating metal in the Barbier reaction of carbonyl compounds with allyl halides was reported in this paper. In contrast to the traditional metal-mediated or catalyzed Barbier reactions, exclusive α-adducts were obtained in this one-pot reaction with a broad scope of substrates and feasible reaction conditions.

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An organocatalytic atroposelective strategy for accessing enantioenriched axially chiral IAN analogues was developed for the first time. A class of novel atropisomeric C2arylquinoline skeletons were synthesized with high enantiocontrol via chiral phosphoric-acid-catalyzed heteroannulation of in situ generated vinylidene ortho-quinone methide (VQM) intermediates with ortho-aminophenones. The strategy tolerated a broad substrate scope, providing a facile organocatalytic approach to IAN analogues in good yields and excellent enantioselectivities under mild reaction conditions. Moreover, the synthetic utility of this methodology was illustrated through further transformations into IAN-type ligand and axially chiral thiourea. Research on axially chiral biaryls has developed rapidly and gained considerable momentum in recent years because of their widespread appearance in natural products, [1] bioactive molecules, [2] and privileged chiral ligands and catalysts. [3] In sharp contrast, the asymmetric construction of axially chiral heterobiaryls was still underdeveloped, [4] even though it is scientifically important and of great significance in practical application. [5] For instance, the effective approaches to access axially chiral 2-arylpyridines (isoquinolines) are especially scanty, while they have emerged as essential backbone of numerous chiral catalysts and ligands in asymmetric catalysis (Figure 1). [6] This type of heteroaryl atropisomers ordinarily formed a chelate ring with metal atom through the coordination of nitrogen and other donor atoms, such as phosphorus, nitrogen, oxygen, and sulfur, providing the asymmetric induction in various metal-catalyzed enantioselective transformations (Figure 2 a). [7] Conventionally, synthetic approaches for enantioenriched 2-arylpyridine/isoquinoline skeletons depend mainly on transition-metal mediated patterns, such as cross-coupling, [6i,r] (dynamic) kinetic resolution/ transformation, [6a,g,h,j-q,s] and de novo construction of a (hetero)aromatic ring.