Exploring Hydrocarboxylation Of Olefins

Carbonylation reaction,is a kind of important elementary reaction,which has become the fundamental process in organic and industrial synthesis.The carbonylation of alkenes has been widely investigated because of its atom economy.Significant progress has been made in this field,and the use of carbonylation process to synthesize all kinds of complicated complex via simple molecule containing carbonyl group becomes more important.However,the toxic flammable CO gas has some real difficulties in operation,storage and transport.The difficulties hinder the overall application of carbonylation in the laboratory and industry.Therefore,developing carbonylations in a safer,easier and more effective way,without using CO gas,is highly desired and has become the hot research topic.This dissertation mainly focused on regioselective carbonylation without CO and contained the following three parts:1.We have developed an efficient Pd-catalyzed hydrocarboxylation of enimides with HCOOH and a catalytic amount of HCOOPh.The reaction is operationally simple and requires no handling of toxic CO gas.Various substituted N-vinylphthalimides can be efficiently hydrocarboxylated with 0.5 mol%(?3-C3H5)2Pd2Cl2,2 mol%DPEphos,2 equiv HCOOH,and 0.2 equiv HCOOPh,giving the corresponding carboxylic acids in 60-98%yield with high regioselectivities,which provides a useful route to the ?3-amino acids and their derivatives.The phthalimide was readily hydrolyzed to the corresponding ?-amino acids with hydrazine hydrate in ethanol in 98%yield.The 1,1-disubstituted enimides can be efficiently hydroesterificationed with 2.5 mol%(?3-C3H5)2Pd2Cl2,10 mol%DPEphos,and 1.2 equiv HCOOPh,giving the corresponding esters with high regioselectivities.2.We have developed an effective route to ?2-amino acid derivatives via Pd-Catalyzed regioselective hydrocarboxylation of 1,2-disubstituted enimides.?-Amino acids are important functional moieties that present in various biologically and pharmaceutically active compounds.Hydrocarboxylation of 1,2-disubstituted enimides presents an attractive approach to this class of compound.The reaction requires no handling of toxic CO gas and is operationally simple.The reactivity of hydrocarboxylation was found to be highly dependent on the ligand used.A variety of ?2-amino acid derivatives have been obtained in 68-99%yield with high regioselectivity while 1,2-disubstituted enimides were hydrocarboxylated with APD(2.5 mol%),PPh3(20 mol%),HCOOH(2.0 equiv)and HCOOPh(1.2 equiv).Furthermore,the cis enimides were also highly effective substrates.The corresponding ?2-amino acid can be obtained in 98%yield while the phthalilide was readily hydrolyzed with hydrazine hydrate in ethanol.3 We have investigated the carbonylation of 1,2-disubstituted aromatic alkenes.The reactivity of symmetric 1,2-disubstitiuted aromatic alkenes have been improved by the optimization of reaction parameters such as palladium catalyst,ligand and reaction temperature.However,the reactivity and regioselectivity of unsymmetrical 1,2-disubstituted aromatic alkenes have not been solved which need to futher study.