Enantioselective one-pot synthesis of 4<i>H</i>-chromene derivatives catalyzed by a chiral Ni(<scp>ii</scp>) complex
作者:Xuan Yu、Wenjie Lan、Jiaqi Li、Hui Bai、Zhaohai Qin、Bin Fu
DOI:10.1039/d0ra08906k
日期:——
A Ni(II)–bis(oxazoline) complex and p-TSOH are used to form enantioenriched 4H-chromenes from ortho-quinone methides (o-QMs) and dicarbonyls, providing the desired products in up to 95% ee. The method is compatible with various β-ketoester substrates, and the products obtained could be converted into biologically active 4H-chromene derivatives.
Ni( II )-双(恶唑啉)配合物和p -TSOH 用于从邻醌甲基化物 ( o -QMs) 和二羰基化合物中形成富含对映体的 4 H-色烯,从而提供高达 95% ee 的所需产物。该方法与多种β-酮酯底物相容,所得产物可转化为具有生物活性的4H-色烯衍生物。
Bis(imidazolidine)pyridine‐CoCl
<sub>2</sub>
: A Novel, Catalytically Active Neutral Complex for Asymmetric Michael Reaction of 1,3‐Carbonyl Compounds with Nitroalkenes
作者:Takayoshi Arai、Yuko Iimori、Mayu Shirasugi、Ryota Shinohara、Yuri Takagi、Takumi Suzuki、Junma Ma、Satoru Kuwano、Hyuma Masu
DOI:10.1002/adsc.201900421
日期:2019.8.21
A neutral bis(imidazolidine)pyridine (PyBidine)‐CoCl2 complex showed catalytic activity for the Michael reaction of malonates with nitroalkenes. The results indicated that a weak amine base aided enolate formation from the neutral complex, in which the N−H proton of the imidazolidine ligand played a significant role.
Asymmetric Organocatalytic [4 + 1] Annulations: Enantioselective Construction of Multifunctionalized Spirocyclopentane Oxindoles Bearing α,α-Disubstituted α-Amino-β-keto Esters
作者:Chuan-Chuan Wang、Jian Huang、Xin-Hao Li、Søren Kramer、Guo-Qiang Lin、Xing-Wen Sun
DOI:10.1021/acs.orglett.8b00927
日期:2018.5.18
α-disubstituted α-amino-β-keto esters was achieved through [4 + 1] annulation of oxindoles and α-imine-β-oxo-γ,δ-unsaturated esters under mild conditions in good yields (up to 82%) and stereoselectivities (up to >20:1 dr, 96% ee). The reaction is amenable to gram scale synthesis using catalyst loading as low as 1 mol %. The corresponding chiral α,α-disubstituted α-amino-β-keto esters could be easily transformed
通过在温和的条件下,于[4 +1]环化吲哚和α-亚胺-β-氧代-γ,δ-不饱和酯,可以实现具有α,α-二取代的α-氨基-β-酮基酯的螺硫辛酯的高对映选择性。良率(高达82%)和立体选择性(高达> 20:1 dr,96%ee)。该反应适合于使用低至1mol%的催化剂负载进行克规模的合成。相应的手性α,α-二取代的α-氨基-β-酮基酯可以很容易地转化为环戊[ b ]吲哚衍生物,而不会破坏对映体纯度。
Phosphine-Catalyzed Remote 1,7-Addition for Synthesis of Diene Carboxylates
作者:Jiaxu Feng、You Huang
DOI:10.1021/acscatal.0c00588
日期:2020.3.20
phosphine-catalyzed remote 1,7-addition of vinyl allenoates has been developed, providing a series of 1,3-dienes derivatives in high yields (up to 99%) and with good chemo-, regio-, and stereoselectivity. This reaction demonstrated that the introduction of vinyl in allenoates effectively extended reaction types of phosphine-catalyzed nucleophilic addition of allenoates, leading to concise synthesis of diene carboxylates
A General Organocatalyzed Michael–Michael Cascade Reaction Generates Functionalized Cyclohexenes
作者:Patrick G. McGarraugh、Joshua H. Jones、Stacey E. Brenner-Moyer
DOI:10.1021/jo201140a
日期:2011.8.5
to α,β-unsaturatedaldehydes are susceptible to multiple subsequent reaction pathways. We designed cyclic unsaturated β-ketoester substrates that enabled the development of the first diphenyl prolinol silyl ether catalyzed Michael–Michael cascadereaction initiated by a β-dicarbonyl Michael donor to form cyclohexene products. The reaction conditions we developed for this Michael–Michael cascade reaction