Palladium-Catalyzed Asymmetric [8+2] Dipolar Cycloadditions of Vinyl Carbamates and Photogenerated Ketenes

Higher-order cycloadditions, particularly [8+2] cycloadditions, are a straightforward and efficient strategy for constructing significant medium-sized architectures. Typically, configuration-restrained conjugated systems are utilized as 8π-components for higher-order concerted cycloadditions. However, for this reason, 10-membered monocyclic skeletons have never been constructed via catalytic asymmetric [8+2] cycloaddition with high peri- and stereoselectivity. Here, we accomplished an enantioselective [8+2] dipolar cycloaddition via the merger of visible-light activation and asymmetric palladium catalysis. This protocol provides a new route to 10-membered monocyclic architectures bearing chiral quaternary stereocenters with high chemo-, peri-, and enantioselectivity. The success of this strategy relied on the facile in situ generation of Pd-containing 1,8-dipoles and their enantioselective trapping by ketene dipolarophiles, which were formed in situ via a photo-Wolff rearrangement.     

Visible Light Induced Copper-Catalyzed Enantioselective Deaminative Arylation of Amino Acid Derivatives Assisted by Phenol

The exploration of value-added conversions of naturally abundant amino acids has received considerable attention from the synthetic community. Compared with the well-established asymmetric decarboxylative transformation, the asymmetric deaminative transformation of amino acids still remains a formidable challenge, mainly due to the lack of effective strategies for the C−N bond activation and the potential incompatibility with chiral catalysts. Here, we disclose a photoinduced Cu-catalyzed asymmetric deaminative coupling reaction of amino acids with arylboronic acids. This new protocol provides a series of significant chiral phenylacetamides in generally good yields and excellent stereoselectivity under mild and green conditions (42–85 % yields, up to 97 % ee). Experimental investigations and theoretical calculations were performed to reveal the crucial role of additional phenols in improving catalytic efficiency and enantiocontrol.     

Photocatalytic aerobic oxidation/semipinacol rearrangement sequence: a concise route to the core of pseudoindoxyl alkaloids

A visible light-induced photocatalytic aerobic oxidation/semipinacol rearrangement has been successfully developed. This methodology allows for efficient conversion of a wide range of indoles into the synthetically significant 2,2-disubstituted indolin-3-ones, the core structure of pseudoindoxyl alkaloids, under mild reaction conditions.     

Visible light-induced intramolecular cyclization reactions of diamines: a new strategy to construct tetrahydroimidazoles

A new and efficient synthesis of highly substituted tetrahydroimidazole derivatives by means of visible light-induced intramolecular cyclization reactions has been described. This photoredox catalytic reaction exhibited high diastereoselectivity and afforded the desired products in good yields.     

Light opens a new window for N-heterocyclic carbene catalysis

N-Heterocyclic carbenes (NHCs) are efficient Lewis basic catalysts for the umpolung of various polarized unsaturated compounds usually including aldehydes, imines, acyl chlorides and activated esters. NHC catalysis involving electron pair transfer steps has been extensively studied; however, NHC catalysis through single-electron transfer (SET) processes, despite having the potential to achieve chemical transformations of inert chemical bonds and using green reagents, has long been a challenging task in organic synthesis. In parallel, visible-light-induced photocatalysis and photoexcitation have been established as powerful tools to facilitate sustainable organic synthesis, as they enable the generation of various reactive radical intermediates under extremely mild conditions. Recently, a number of elegant visible-light-induced, NHC-catalyzed transformations were developed for accessing valuable organic compounds. As a result, this minireview will highlight the recent advances in this field.

This minireview summarized the recent advances on the photoinduced, NHC-catalyzed organic reactions according to the function of visible light.     

Enantioselective cascade reactions of stable sulfur ylides and nitroolefins through an axial-to-central chirality transfer strategy

An enantioselective [4 + 1] annulation/rearrangement cascade of stable sulfur ylides and nitroolefins has been developed through an efficient axial-to-central chirality transfer with the use of a chiral BINOL-derived sulfide as a reliable stereocontroller. It can provide pharmaceutically and synthetically important oxazolidinones in high stereoselectivities (up to 96:4 e.r. and >95:5 d.r.). Moreover, this strategy was also successfully applied to the asymmetric [4 + 1]/[3 + 2] cycloaddition cascade of sulfur ylides with alkene-tethered nitroolefins, and the corresponding enantioenriched fused heterocycles (up to 87:13 e.r. and >95:5 d.r.) were obtained in good to excellent yields (54-95% yields).     

过渡金属与有机小分子协同催化的不对称烯丙基取代反应研究进展

过渡金属催化是现代有机合成化学中精准构建化学键最重要的工具之一.有机小分子催化是21世纪初开始蓬勃发展的一个新兴研究领域.两者在不对称烯丙基化反应中的完美结合有意义地解决了该领域亲核试剂的普适性、立体选择性控制等挑战性问题.本文综述了过渡金属与有机小分子协同催化的不对称烯丙基化反应研究进展.按照不同的手性控制方式（过渡金属催化剂控制手性、有机小分子催化剂控制手性以及两者共同控制手性）对这些反应进行了梳理和总结,同时对代表性反应的机理以及该领域仍然存在的问题与未来发展进行了简单阐述.     

Visible light-driven organic photochemical synthesis in China

In recent years, visible light-driven organic photochemical synthesis has attracted wide research interest from academic and industrial communities due to its features of green and sustainable chemistry. In this flourishing area, Chinese chemists have devoted great efforts to different aspects of synthetic chemistry. This review will summarize their representative work according to the following categories: C–H functionalization, synthesis of aromatic aza-heterocycles, asymmetric organic photochemical synthesis, transformations of small molecules and biomolecule-compatible reactions.