An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine o...An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.展开更多
Cinchona alkaloids are utilized as chiral ligands to promote the enantioselective addition of dialkylzinc to N-diphenylphos-phinylimines affording enantiomerically enriched N-diphenyl-phosphinylamines in up to 91% ee.
Chiral phase-transfer catalysts, derived from cinchona alkaloids and Fréchet dendritic wedges up to generation two, have been synthesized. These chiral dendritic molecules have been used as PTCs in the epoxidatio...Chiral phase-transfer catalysts, derived from cinchona alkaloids and Fréchet dendritic wedges up to generation two, have been synthesized. These chiral dendritic molecules have been used as PTCs in the epoxidation of α, β-enones, showing a moderate level of asymmetric induction.展开更多
The first direct asymmetric Mannich reaction of malononitrile to N-Boc-protected imines has been developed with cinchona alkaloid as catalyst. The procedure could tolerate a relatively wide range of substrates, and re...The first direct asymmetric Mannich reaction of malononitrile to N-Boc-protected imines has been developed with cinchona alkaloid as catalyst. The procedure could tolerate a relatively wide range of substrates, and results in excellent yields and good enantioselectivities even in the presence of only 1 mol% of catalyst loading. The present work provides an easy access to β-amino malononitrile derivatives.展开更多
Optically active terminal 1,2-diols were prepared with high enantiopurity via the TMS-quinidine-catalyzed en- antioselective cyclization of acyl chlorides and oxaziridine, followed by reductive ring-opening of the cyc...Optically active terminal 1,2-diols were prepared with high enantiopurity via the TMS-quinidine-catalyzed en- antioselective cyclization of acyl chlorides and oxaziridine, followed by reductive ring-opening of the cycloadducts.展开更多
Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents. These monophosphinites were provided in one pot with the yields ranged from 63% to 75%. Their structures were ...Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents. These monophosphinites were provided in one pot with the yields ranged from 63% to 75%. Their structures were confirmed by NMR spectroscopy and HRMS. C 2009 Sheng Yong Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The...The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).展开更多
基金the National Natural Science Foundation of China (No.20672141) for financial support of this work.
文摘An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.
基金Project supported by the National Natural Science Foundation of China(No.20102005).
文摘Cinchona alkaloids are utilized as chiral ligands to promote the enantioselective addition of dialkylzinc to N-diphenylphos-phinylimines affording enantiomerically enriched N-diphenyl-phosphinylamines in up to 91% ee.
文摘Chiral phase-transfer catalysts, derived from cinchona alkaloids and Fréchet dendritic wedges up to generation two, have been synthesized. These chiral dendritic molecules have been used as PTCs in the epoxidation of α, β-enones, showing a moderate level of asymmetric induction.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China （No. 21102071） and the Fundamental Research Funds for the Central Universities （Nos. 1107020522 and 1082020502）. The Jiangsu 333 program （for Pan） and Changzhou Jin-Feng-Huang program （for Han） are also acknowledged.
文摘The first direct asymmetric Mannich reaction of malononitrile to N-Boc-protected imines has been developed with cinchona alkaloid as catalyst. The procedure could tolerate a relatively wide range of substrates, and results in excellent yields and good enantioselectivities even in the presence of only 1 mol% of catalyst loading. The present work provides an easy access to β-amino malononitrile derivatives.
基金Acknowledgement This work was supported by the National Natural Science Foundation of China （No. 21072195） and the Major State Basic Research Development Program （No. 2011CB808600）.
文摘Optically active terminal 1,2-diols were prepared with high enantiopurity via the TMS-quinidine-catalyzed en- antioselective cyclization of acyl chlorides and oxaziridine, followed by reductive ring-opening of the cycloadducts.
基金the National Natural Science Foundation of China(Nos.20842007,30600163)Natural Science Basic Research Plan in Shaanxi Province of China(No.SJ08-ZT02) for financial support.
文摘Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents. These monophosphinites were provided in one pot with the yields ranged from 63% to 75%. Their structures were confirmed by NMR spectroscopy and HRMS. C 2009 Sheng Yong Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金financially Supported by the National Natural Science Foundation of China (20772084)
文摘The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).
