A series of C_2-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,~1H NMR,^（13）C NMR,MS spectra and el...A series of C_2-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,~1H NMR,^（13）C NMR,MS spectra and elemental analyses.The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc,the corresponding sec-alcohols were gained with excellent enantioselectivities（up to 87.1%ee） and high yields（up to 76.7%） after the conditions were optimized.展开更多
The novel well-defined chiral bicyclic thioureas based on enantiopure unsymmetric cis-2,5-disustituted pyrrolidine skeleton were firstly synthesized and fully characterized by their 1H NMR, 13C NMR and HRMS. Their abs...The novel well-defined chiral bicyclic thioureas based on enantiopure unsymmetric cis-2,5-disustituted pyrrolidine skeleton were firstly synthesized and fully characterized by their 1H NMR, 13C NMR and HRMS. Their absolute configurations were also determined by single-crystal X-ray analysis.展开更多
Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enant...Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enantiose-lectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with het-erocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst.展开更多
A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee value...A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee values and yields,a much better result than previously reported.Furthermore,through theoretical analysis,literature research and experimental verifications,a new mechanism involving an inverse-electron-demand Diels–Alder（IEDDAR） and a retro-Henry reaction was proposed.展开更多
基金Open-Ended Fund of the State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology
文摘A series of C_2-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,~1H NMR,^（13）C NMR,MS spectra and elemental analyses.The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc,the corresponding sec-alcohols were gained with excellent enantioselectivities（up to 87.1%ee） and high yields（up to 76.7%） after the conditions were optimized.
文摘The novel well-defined chiral bicyclic thioureas based on enantiopure unsymmetric cis-2,5-disustituted pyrrolidine skeleton were firstly synthesized and fully characterized by their 1H NMR, 13C NMR and HRMS. Their absolute configurations were also determined by single-crystal X-ray analysis.
基金Project supported by the National Key Project for Basic Research （No. 2010CB126105）, Key Technologies R＆D Program （No. 2011BAE06B05）, the National Natural Science Foundation of China （No. 20872021） and Innovation Foundation for Graduate Students in Guizhou University （No. 2010023）.
文摘Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enantiose-lectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with het-erocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst.
基金the National Natural Science Foundation of China (Nos. 21071068 and 21372107)the Fundamental Research Funds for the Central Universities (No. lzujbky-2012-k08)
文摘A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee values and yields,a much better result than previously reported.Furthermore,through theoretical analysis,literature research and experimental verifications,a new mechanism involving an inverse-electron-demand Diels–Alder（IEDDAR） and a retro-Henry reaction was proposed.
