An indium complex of chiral pyridine bis（oxazoline） （PYBOX） has been applied to the catalytic asymmetric allylation of ketones. It has been found that this chiral indium complex is strong enough to promote the rea...An indium complex of chiral pyridine bis（oxazoline） （PYBOX） has been applied to the catalytic asymmetric allylation of ketones. It has been found that this chiral indium complex is strong enough to promote the reaction of ketones with allyltributylstannane smoothly. The products were obtained in moderate yields with low to moderate enantioselectivities.展开更多
Organosilanes are not found in nature but play a crucial role in the sustainable development of modern society.Si-chiral organosilanes represent a type of novel chemical space that is highly desirable for research ori...Organosilanes are not found in nature but play a crucial role in the sustainable development of modern society.Si-chiral organosilanes represent a type of novel chemical space that is highly desirable for research oriented in terms of their properties,including synthetic chemistry,drug discovery,and materials and life sciences.While much effort has been given to the catalytic enantioselective construction of Si-chirality,the facile synthesis of multifunctional Si-chiral silanes remains undeveloped.Here,we report an unprecedented highly enantioselective copper-catalyzed desymmetric sulfonylation or acylation of prochiral 1,3-siladiols for the expedient synthesis of multifunctional Si-chiral silanes with both a hydroxymethyl group and an ester group as synthetic handles.A one-pot tandem desymmetric sulfonylation/substitution sequence,internally reusing waste chloride or bromide formed from the upstream sulfonylation step as the reagent for a substitution step,is also exploited for the atom-efficient synthesis of Si-chiral silylmethanols featuring a chloromethyl or bromomethyl group.A newly developed sterically confined pyridine-bis(oxazoline)(PYBOX)ligand with a bulky C4 amide-containing shielding group is crucial for achieving excellent reactivity and enantioselectivity.The scale-up synthesis and various diversifying elaborations of multifunctional Si-chiral silylmethanols further highlight the synthetic practicability of this protocol.展开更多
Scandium-catalyzed asymmetric Claisen rearrangement reactions of 2-allyloxyindoles and 2-propargyloxyin- doles provide a novel approach to diverse 3-allyloxindoles and 3-allenyloxindoles in excellent yields （up to 99...Scandium-catalyzed asymmetric Claisen rearrangement reactions of 2-allyloxyindoles and 2-propargyloxyin- doles provide a novel approach to diverse 3-allyloxindoles and 3-allenyloxindoles in excellent yields （up to 99%） and enantioselectivity （up to 99% ee） under mild reaction conditions. The scandium catalyst was derived from Sc（OTf）3 and Pybox ligand.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20472062） and the Natural Science Foundation of Education Committee of Jiangsu Province （No. 05KJB150116）.
文摘An indium complex of chiral pyridine bis（oxazoline） （PYBOX） has been applied to the catalytic asymmetric allylation of ketones. It has been found that this chiral indium complex is strong enough to promote the reaction of ketones with allyltributylstannane smoothly. The products were obtained in moderate yields with low to moderate enantioselectivities.
基金supported by the National Natural Science Foundation of China(22471073,22171087)the Technology Innovation Project of Shanghai Municipal Agricultural Committee(HNK(T2023302))+2 种基金the Innovation Program of Shanghai Municipal Education Commission(2023ZKZD37)the Ministry of Education(PCSIRT)the Fundamental Research Funds for the Central Universities。
文摘Organosilanes are not found in nature but play a crucial role in the sustainable development of modern society.Si-chiral organosilanes represent a type of novel chemical space that is highly desirable for research oriented in terms of their properties,including synthetic chemistry,drug discovery,and materials and life sciences.While much effort has been given to the catalytic enantioselective construction of Si-chirality,the facile synthesis of multifunctional Si-chiral silanes remains undeveloped.Here,we report an unprecedented highly enantioselective copper-catalyzed desymmetric sulfonylation or acylation of prochiral 1,3-siladiols for the expedient synthesis of multifunctional Si-chiral silanes with both a hydroxymethyl group and an ester group as synthetic handles.A one-pot tandem desymmetric sulfonylation/substitution sequence,internally reusing waste chloride or bromide formed from the upstream sulfonylation step as the reagent for a substitution step,is also exploited for the atom-efficient synthesis of Si-chiral silylmethanols featuring a chloromethyl or bromomethyl group.A newly developed sterically confined pyridine-bis(oxazoline)(PYBOX)ligand with a bulky C4 amide-containing shielding group is crucial for achieving excellent reactivity and enantioselectivity.The scale-up synthesis and various diversifying elaborations of multifunctional Si-chiral silylmethanols further highlight the synthetic practicability of this protocol.
文摘Scandium-catalyzed asymmetric Claisen rearrangement reactions of 2-allyloxyindoles and 2-propargyloxyin- doles provide a novel approach to diverse 3-allyloxindoles and 3-allenyloxindoles in excellent yields （up to 99%） and enantioselectivity （up to 99% ee） under mild reaction conditions. The scandium catalyst was derived from Sc（OTf）3 and Pybox ligand.
