Immobilized asymmetric hydrogen transfer catalyst was synthesized by surface modification of mesoporous molecular sieve MCM-41 using 3-cholorpropyl-triethoxysilane as modifier, and then being treated with (1R, 2R)-1,2...Immobilized asymmetric hydrogen transfer catalyst was synthesized by surface modification of mesoporous molecular sieve MCM-41 using 3-cholorpropyl-triethoxysilane as modifier, and then being treated with (1R, 2R)-1,2-diaminocyclohexane and dichloro(p-cymene)-ruthenium dimmer successively. The prepared catalyst was characterized by means of FT-IR, PXRD and N\-2 adsorption-desorption isotherms, and was applied in asymmetric hydrogen transfer reaction of reduction of acetophenone to α-phenyl ethanol. It showed a average conversion of 4.02% and 15.23% of ee in all 3 performances. The conversion was almost the same as its corresponding homogenous counterpart, while the ee was somewhat lower.展开更多
The discovery of the novel reactivity of conjugated enynes,mediated by readily available halogenation reagents,opens a broad range of mechanistically unique pathways for the synthesis of highly functionalized chiral a...The discovery of the novel reactivity of conjugated enynes,mediated by readily available halogenation reagents,opens a broad range of mechanistically unique pathways for the synthesis of highly functionalized chiral allene derivatives.Bromoallenyl pyrrolidines can be synthesized via 1,4-addition of sulfonamide nitrogen nucleophiles and halogens to conjugated enynes.This process can lead to simultaneous formation of a highly functionalized axially chiral allene and a stereogenic center under economical and environmentally friendly reaction conditions.展开更多
文摘Immobilized asymmetric hydrogen transfer catalyst was synthesized by surface modification of mesoporous molecular sieve MCM-41 using 3-cholorpropyl-triethoxysilane as modifier, and then being treated with (1R, 2R)-1,2-diaminocyclohexane and dichloro(p-cymene)-ruthenium dimmer successively. The prepared catalyst was characterized by means of FT-IR, PXRD and N\-2 adsorption-desorption isotherms, and was applied in asymmetric hydrogen transfer reaction of reduction of acetophenone to α-phenyl ethanol. It showed a average conversion of 4.02% and 15.23% of ee in all 3 performances. The conversion was almost the same as its corresponding homogenous counterpart, while the ee was somewhat lower.
基金the University of Wisconsin-Madison and the American Chemical Society Petroleum Research Fund (48092-G) for funding
文摘The discovery of the novel reactivity of conjugated enynes,mediated by readily available halogenation reagents,opens a broad range of mechanistically unique pathways for the synthesis of highly functionalized chiral allene derivatives.Bromoallenyl pyrrolidines can be synthesized via 1,4-addition of sulfonamide nitrogen nucleophiles and halogens to conjugated enynes.This process can lead to simultaneous formation of a highly functionalized axially chiral allene and a stereogenic center under economical and environmentally friendly reaction conditions.
