| Chiral organoboronates not only possess unique biological activities and catalytic properties,but also serve as key intermediates,participating in a series of stereoselective and stereospecific transformations,converting carbon-boron bonds to carbon-carbon bonds and other carbon-heteroatoms bonds.A great deal of effort has been devoted to developing synthetic methods for these optically active organoboron compounds over the past few decades.Among the reported methods,asymmetric catalysis has emerged as a practical and efficient preparation method,such as asymmetric boron addition reaction,asymmetric allyl boronation reaction and stereospecific cross-coupling boronation reaction,etc.However,most of these methods require transition metal catalysis.In this paper,a transition metal-free carbene-catalyzed asymmetric boronation of para-quinone methides(p-QMs)was realized.Organosilicon compounds are an important part of research in organic chemistry,materials science and medicinal chemistry.Studies have shown that the introduction of silicon-containing groups into organic molecules can change their solubility,stability and pharmacokinetic properties.In recent years,people have devoted themselves to exploring the synthesis methods of these organosilicon compounds.In recent years,the synthesis methods mainly focus on the addition reaction of silane to unsaturated bonds.The paper mainly includes the following contents:Chapter 1 Research BackgroundThe asymmetric boronation and asymmetric silylation reactions in the past ten years were reviewed,and the research progress of the two asymmetric reactions was summarized.Chapter 2 Experimental PreparationThe reagents and instruments used in the experiments were summarized,the synthesis steps of the substrates were introduced in detail,and the drying methods of the solvents used in the experiments were also described.Chapter 3 Carbene-catalyzed asymmetric boronation of p-QMsThe asymmetric boronation of p-QMs was catalyzed by commercial chiral triazole salts,and the optimal conditions of the reaction were determined by optimizing the conditions.The method does not require transition metal catalysis,and has good compatibility with aromatic,aliphatic,heterocyclic and fused-ring substrates.The applicability of the reaction was further studied,including the study of 0.1%catalyst amount and the gram scale scale-up reaction.Chapter 4 Copper Carbene Catalyzed Asymmetric Silylation of Alkenyl Phosphine OxidesThe synthesis of β-silylphosphine oxides was catalyzed by cuprous cyanide in excellent yields(up to 96%).Then,a commercial chiral triazole carbene precursor was used to generate copper carbene in situ,and the asymmetric silicon addition reaction of alkenylphosphine oxide was catalyzed under the optimal conditions of screening.The reaction achieved excellent yield and enantioselectivity,and the ee value was up to 92%,and the reaction had good compatibility with aromatic and fused-ring substrates.The innovation of the paper:1.The reported asymmetric boronation of p-QMs requires transition metal catalysis.The method in this paper does not require transition metal catalysis,which is in line with the development concept of green chemistry.2.When the substrate is scaled up to the gram level and the catalyst dosage is reduced to 0.1%,the reaction proceeded very well without obvious erosion of yield and enantioselectivity.3.For the first time,the copper carbene-catalyzed silylation of alkenylphosphine oxides was reported,in which the enantioselectivity of the asymmetric reaction was up to 92%. |
