Co-catalyst Separated By Hollow-shell Silicon For Two-step Sequential Reaction To Prepare Chiral Alcohols And Amine

Chiral alcohols and chiral amines play an important role in the organic synthesis of biomedicine,natural products,fine chemicals and asymmetric catalysis.However,the current method of homogeneous catalysis is used to construct 1,4-stereocenters of chiral alcohol and alkyne to chiral amines in one pot has big challenge,because it is quite difficult for different homogeneous catalysts to carry out two-step continuous conversion in a one-pot system.Based on this,this dissertation aims to design a separated co-catalyst system,using mesoporous silicon nanosphere as the support,and in situ synthesizing a co-catalyst system composed of chiral diamine ruthenium and chiral amide,Au-NHC and amine dehydrogenase to solve the problem of incompatibility of homogeneous catalysts in a one-pot system,and prepared high valueadded chiral alcohol and chiral amine in a two-step continuous reaction.The specific work is as follows:(1)Using the ambient function mesoporous silicon nanosphere as the support,a separate co-catalyst system consisting of a supported chiral diamine ruthenium and a chiral square amide catalyst is designed,and the chiral square amide catalyst with Michael’s addition catalytic activity and the ruthenium catalyst with asymmetric hydrogen transfer catalytic activity are encapsulated in the cavity of the empty shell mesoporous silicon nanosphere by encapsulation.The outer layer of ruthenium catalyst encapsulated by its interpore silicon nanosphere modifies a polymer with temperature responsive,which can be relaxed at high temperatures and contracted at low temperatures,thereby achieving the active regulation of catalysts at high and low temperatures.The morphological structure,specific surface area,pore volume and pore size of the divided chiral diamine ruthenium and chiral square amide catalysts were systematically studied through different characterization tests.By α,β-unsaturated enone and α-nitrosulfone perform a two-step continuous reaction of Michael’s addition/asymmetric hydrogen transfer in a pot of cocatalytic systems,constructing a series of chiral alcohols with 1,4-stereocentric centers at high yield(up to 98%),high enantioselectivity(up to 99% ee),and high diastereoselectivity(up to 98:2 dr).(2)Using the environmental function mesoporous silicon nanosphere as the support,a divided co-catalyst system composed of a supported Au-NHC catalyst and an amine dehydrogenase is designed,and the homogeneous Au-NHC catalyst is encapsulated in the cavity of the empty shell mesoporous silicon nanosphere by using the synthesis method in situ,which can eliminate the interaction between the Au-NHC catalyst and the amine dehydrogenase and solve the inherent conflict between them.In addition,this hydrophilic mesoporous silicon nanosphere can also use an aqueous solution as a catalytic environment to overcome the conflict of external reaction conditions.Through a series of different characterization tests,the morphological structure,bond energy,pore size,specific surface area and other characteristics of the loaded Au-NHC catalyst were studied.Under cocatalytic conditions,the hydrolysis/reduction amination of propyl ether feedstock in buffer solution was realized in a two-step continuous reaction,and a series of chiral amines were constructed with high yield(up to 98%),high enantioselectivity(up to 99% ee).