70254-42-1Relevant articles and documents
Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
supporting information, p. 16470 - 16485 (2021/10/20)
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
Efficient visible light mediated synthesis of quinolin-2(1H)-ones from quinolineN-oxides
Bhuyan, Samuzal,Chhetri, Karan,Hossain, Jagir,Jana, Saibal,Mandal, Susanta,Roy, Biswajit Gopal
supporting information, p. 5049 - 5055 (2021/07/29)
Quinolin-2(1H)-ones are one of the important classes of compounds due to their prevalence in natural products and in pharmacologically useful compounds. Here we present an unconventional and hitherto unknown photocatalytic approach to their synthesis from easily available quinoline-N-oxides. This reagent free highly atom economical photocatalytic method, with low catalyst loading, high yield and no undesirable by-product, provides an efficient greener alternative to all conventional synthesis reported to date. The robustness of the methodology has been successfully demonstrated with easy scaling up to the gram scale.
Manganese-Promoted Regioselective Direct C3-Phosphinoylation of 2-Pyridones
Chantarojsiri, Teera,Kittikool, Tanakorn,Phakdeeyothin, Kunita,Yotphan, Sirilata
supporting information, p. 3071 - 3078 (2021/07/22)
A highly efficient and regioselective manganese-induced radical oxidative direct C?P bond formation between 2-pyridones and secondary phosphine oxides was developed. The C3-selective phosphinoylation was conveniently achieved through a combination of substoichiometric manganese and persulfate oxidant under mild conditions. Various 3-phosphinoylated pyridone products can be obtained in moderate to high yields. Preliminary mechanistic studies suggest that the reaction is likely to involve a radical pathway induced by catalytically active Mn3+ species.
