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Haijian Yu Qiaohui Wang Prof. Youming Wang Prof. Haibing Song Prof. Zhenghong Zhou Prof. Chuchi Tang 《化学:亚洲杂志》2013,8(11):2859-2863
A highly diastereo‐ and enantioselective cyclopropanation of β,γ‐unsaturated α‐ketoesters with bromonitromethane has been successfully developed through a domino Michael‐addition/intramolecular‐alkylation strategy. Acceptable yields (up to 89 %) and enantioselectivities (up to 96 % ee) have been obtained. 相似文献
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Direct Catalytic Asymmetric Vinylogous Conjugate Addition of Unsaturated Butyrolactones to α,β‐Unsaturated Thioamides 下载免费PDF全文
Dr. Liang Yin Dr. Hisashi Takada Shaoquan Lin Dr. Naoya Kumagai Prof. Dr. Masakatsu Shibasaki 《Angewandte Chemie (International ed. in English)》2014,53(21):5327-5331
Soft Lewis acid/Brønsted base cooperative catalysts have enabled direct catalytic asymmetric vinylogous conjugate addition of α,β‐ and β,γ‐unsaturated butyrolactones to α,β‐unsaturated thioamides with perfect atom economy. When using α‐angelica lactone and its derivatives as pronucleophiles, as little as 0.5 mol % catalyst loading was sufficient to complete the reaction necessary to construct consecutive tri‐ and tetrasubstituted stereogenic centers in a highly diastereo‐ and enantioselective fashion. 相似文献
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Catalytic Enantioselective Conjugate Alkynylation of α,β‐Unsaturated 1,1,1‐Trifluoromethyl Ketones with Terminal Alkynes 下载免费PDF全文
Dr. Amparo Sanz‐Marco Prof. Dr. Gonzalo Blay Prof. Dr. M. Carmen Muñoz Prof. Dr. José R. Pedro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):10057-10064
The first catalytic enantioselective conjugate alkynylation of α,β‐unsaturated 1,1,1‐trifluoromethyl ketones has been carried out. Terminal alkynes and 1,3‐diynes were treated with trifluoromethyl ketones in the presence of a low catalytic load of a CuI‐MeOBIPHEP complex (2.5 mol %) and triethylamine (10 mol %) to give the corresponding trifluoromethyl ketones bearing a propargylic stereogenic center at the β position with good yields and excellent enantiomeric excesses in most of the cases. No 1,2‐addition products were formed under the reaction conditions. The procedure showed broad substrate scope for alkyne, diyne, and enone. A rationale for the observed stereochemistry has been provided. Finally, the potential application of the reaction products in the synthesis of chiral tetrahydrofurans bearing a trifluoromethylated quaternary stereocenter has been devised. 相似文献
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Enantioselective Desymmetrization of Prochiral Cyclohexanones by Organocatalytic Intramolecular Michael Additions to α,β‐Unsaturated Esters 下载免费PDF全文
Adam D. Gammack Yamagata Dr. Swarup Datta Kelvin E. Jackson Linus Stegbauer Dr. Robert S. Paton Prof. Dr. Darren J. Dixon 《Angewandte Chemie (International ed. in English)》2015,54(16):4899-4903
A new catalytic asymmetric desymmetrization reaction for the synthesis of enantioenriched derivatives of 2‐azabicyclo[3.3.1]nonane, a key motif common to many alkaloids, has been developed. Employing a cyclohexanediamine‐derived primary amine organocatalyst, a range of prochiral cyclohexanone derivatives possessing an α,β‐unsaturated ester moiety linked to the 4‐position afforded the bicyclic products, which possess three stereogenic centers, as single diastereoisomers in high enantioselectivity (83–99 % ee) and in good yields (60–90 %). Calculations revealed that stepwise C? C bond formation and proton transfer via a chair‐shaped transition state dictate the exclusive endo selectivity and enabled the development of a highly enantioselective primary amine catalyst. 相似文献
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Enantioselective Copper(I/II)‐Catalyzed Conjugate Addition of Nitro Esters to β,γ‐Unsaturated α‐Ketoesters 下载免费PDF全文
Sheng Zhang Kun Xu Fengfeng Guo Yanbin Hu Prof. Zhenggen Zha Prof. Zhiyong Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):979-982
A highly enantioselective Michael addition of nitroacetates to β,γ‐unsaturated α‐ketoesters was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields with up to 99 % ee. With these densely functionalized products, the chiral cyclic nitrones, which are important synthetic intermediates, can be obtained in one step. 相似文献
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Regio‐ and Stereoselective Conjugate Addition of Aldehydes to β‐Tosyl Enones under the Catalysis of a Binaphthyl‐Modified Chiral Amine 下载免费PDF全文
Dr. Taichi Kano Hisashi Sugimoto Hiroki Maruyama Prof. Keiji Maruoka 《Angewandte Chemie (International ed. in English)》2015,54(29):8462-8465
A simple axially chiral amine catalyst promoted the regio‐, diastereo‐, and enantioselective conjugate addition of aldehydes to β‐tosyl enones, which serve as ynone surrogates. The adducts were readily converted by treatment with L‐selectride into less accessible enones with a γ stereogenic center. Such compounds cannot be prepared through the amine‐catalyzed conjugate addition of aldehydes to ynones. The obtained enones underwent further conjugate addition of diorganozinc compounds in the presence of a copper catalyst. 相似文献
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Xin Feng Hai‐Lei Cui Shi Xu Li Wu Prof. Dr. Ying‐Chun Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(34):10309-10312
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Depeng Zhao Ye Yuan Dr. Albert S. C. Chan Prof. Rui Wang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(12):2738-2741
Zinc benefits : The first catalytic asymmetric phospha‐Michael addition of enones has been developed. Under mild reaction conditions, the γ‐oxo phosphonates could be obtained in high yields (up to 99 %) with excellent enantioselectivities (93–99 % ee; see scheme). The strategy makes the asymmetric synthesis of biologically important phosphonate compounds more accessible.
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Xin Feng Hai‐Lei Cui Shi Xu Li Wu Prof. Dr. Ying‐Chun Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(44):12227-12227
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Highly Asymmetric Michael Addition to α,β‐Unsaturated Ketones Catalyzed by 9‐Amino‐9‐deoxyepiquinine
Jian‐Wu Xie Wei Chen Rui Li Mi Zeng Wei Du Lei Yue Ying‐Chen Chen Prof. Dr. Yong Wu Prof. Dr. Jin Zhu Prof. Jin‐Gen Deng Prof. Dr. 《Angewandte Chemie (International ed. in English)》2007,46(27):5049-5049
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Organocatalytic 1,4‐Addition Reaction of 2‐Formyl(thio)esters to Vinylketones: An Efficient Access to Acyclic Chiral Building Blocks with a Quaternary Carbon Stereocenter 下载免费PDF全文
Toshifumi Tatsumi Dr. Tomonori Misaki Prof. Dr. Takashi Sugimura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18971-18974
2‐Formyl(thio)esters were utilized as pronucleophiles to obtain less‐accessible acyclic chiral building blocks bearing versatile functional groups on a quaternary carbon atom for enantioselective 1,4‐addition to vinylketones. To achieve high enantioselectivity in the present 1,4‐addition reaction, thiourea‐tertiary amines containing a bulky chiral backbone were developed as catalysts, and several derivatizations of the products were performed to demonstrate the synthetic utility of the products. 相似文献
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Hak‐Suk Sim Xinhui Feng Jaesook Yun Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(8):1939-1943
Josi or Mandy? Asymmetric conjugate addition of diboron to acyclic enones catalyzed by copper affords chiral organoboronates that possess a boronate group at the β stereocenter with excellent chemical yields and enantioselectivities (see scheme). This method accommodates the structural variation of acyclic enones and provides access to highly functionalized chiral organoboronates in one step.
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Direct Catalytic Asymmetric Doubly Vinylogous Michael Addition of α,β‐Unsaturated γ‐Butyrolactams to Dienones 下载免费PDF全文
Xiaodong Gu Tingting Guo Yuanyuan Dai Allegra Franchino Jie Fei Chuncheng Zou Prof. Dr. Darren J. Dixon Prof. Dr. Jinxing Ye 《Angewandte Chemie (International ed. in English)》2015,54(35):10249-10253
An asymmetric doubly vinylogous Michael addition (DVMA) of α,β‐unsaturated γ‐butyrolactams to sterically congested β‐substituted cyclic dienones with high site‐, diastereo‐, and enantioselectivity has been achieved. An unprecedented DVMA/vinylogous Michael addition/isomerization cascade reaction affords chiral fused tricyclic γ‐lactams with four newly formed stereocenters. 相似文献
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Depeng Zhao Dr. Yuan Wang Lijuan Mao Rui Wang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10983-10987
The first highly enantioselective phosphonylation of α,β‐unsaturated N‐acylpyrroles has been developed. Excellent yields (91–99 %) and enantioselectivities (up to >99 % enantiomeric excess (ee)) were observed for a broad spectrum of both phosphites and N‐acylpyrroles under mild conditions. In particular, when diethyl phosphite was employed to test the scope of the N‐acylpyrroles, almost optically pure products (98 to >99 % ee) were obtained for 20 examples of N‐acylpyrroles. Moreover, optically pure α‐substituted β‐ or γ‐amino phosphonates can be obtained by several simple transformations of the pyrrolyl phosphonates. The versatility of the N‐acylpyrrole moiety makes the phosphorus adducts powerful chiral building blocks that enable the synthesis of various phosphonate‐containing compounds. Finally, the present strategy can also be applied to the asymmetric hydrophosphonylation of N‐acylimines with high enantioselectivities (93 to >99 % ee). 相似文献