Chiral nitriles are valuable molecules in modern organic synthesis and drug discovery. Selectively differentiating the two nitrile groups of widely available malononitrile derivatives is a straightforward yet underdeveloped route to construct enantioenriched nitriles. Here we report an enantioselective nickel-catalyzed desymmetrization of malononitriles for the generation of nitrile-containing all-carbon quaternary stereocenters. This protocol involves a nickel-catalyzed addition of aryl boronic acids to alkynes, followed by a selective nitrile insertion, providing unprecedented access to enantioenriched 5−7-membered α-cyanocycloenones with a fully substituted olefin from a broad range of substrates. The synthetic utility of these nitrile products is demonstrated by gram-scale synthesis and conversion to several useful functional groups.
Asymmetric hydrophosphination is the most atomically economical and straightforward approach to the construction of chiral organophosphorus compounds. Good stereoselectivities have been achieved in asymmetric hydrophosphination of an electron-deficient CC double bond, but substrates involving nonpolar CC bonds remain difficult and are rarely tackled. Herein, we report asymmetric hydrophosphination of a non-electronically activated double bond with a remarkably high degree of stereocontrol. This strategy offered an expedient and broadly applicable platform to prepare tertiary phosphines in high yields (up to 99% yield) and enantioselectivities (up to 99% ee). Particularly noteworthy is that these tertiary phosphine products were then successfully employed as phosphine ligands in enantioselective metal-catalyzed transformations with a high level of asymmetric induction.
Cyclic
sulfonamides (sultams) play a unique role in drug discovery
and synthetic chemistry. A direct synthesis of sultams by an intramolecular
C(sp3)–H amidation reaction using an iron complex
in situ derived from Fe(ClO4)2 and aminopyridine
ligand is reported. This strategy features a readily available catalyst
and tolerates a broad variety of substrates as demonstrated by 22
examples (up to 89% yield). A one-pot iron-catalyzed amidation/oxidation
procedure for the synthesis of cyclic N-sulfonyl
ketimines is also realized with up to 92% yield (eight examples).
The synthetic utility of the method is validated by a gram-scale reaction
and derivatization of the products to ring-fused sultams.
The chromanone scaffold is a privileged structure in heterocyclic chemistry and drug discovery. A highly efficient copper-catalyzed asymmetric conjugated reduction of chromones is developed to give chiral chromanones with good yields (80-99%) and excellent ee values (94->99% ee). Particularly noteworthy is that chiral thiochromanones are also constructed using this method in 74-87% yields with 96-97% ee. The established asymmetric synthesis paves the way for their further pharmaceutical studies.
Regional remote sensing image products are playing an important role in an increasing number of application fields. Aiming at multi-satellite imaging task planning for large-area image acquisition, this paper proposes a multi-objective modeling method. First, we analyzed the core requirements of regional mapping for multi-satellite imaging mission planning: Full coverage of the target area and low consumption of satellite resources. Second, an optimization model with two objective functions, namely the maximum target area coverage and minimum satellite resource utilization, was established. Using the selection of imaging strips and their swing angles as two types of decision variables, the regional decomposition and satellite resource allocation were integrated into the planning model. Third, two efficient algorithms, Vatti and non-dominated sorting genetic algorithm (NSGA-II), were used for objective function calculation and model solving, respectively. Finally, the experiments used Hubei, Finland, and Congo as the target areas and GF1, GF6, ZY1-02C, and ZY3 as imaging satellites to verify the modeling method proposed in this paper. The experiments showed that the proposed multi-objective modeling method could complete the coverage of regional targets with fewer satellite resources and improve the satellite application efficiency significantly.
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