Asymmetric sequential double Michael reactions of γ,δ-unsaturated β-ketoesters to nitroolefins catalyzed by Ni (II)-diamine complex
作者:Shengying Huang、Karen Scherer、Bukuo Ni
DOI:10.1016/j.catcom.2017.08.024
日期:2017.12
The asymmetric sequential double Michaelreactions of γ,δ-unsaturated β-ketoesters and nitroolefins catalyzed by 2 mol% of readily prepared Ni(II)-bis[(R,R)-N,N′-dibenzylcyclohexane-1,2-diamine] complex and then with 1 equivalent of tetramethylguanidine (TMG) for cyclization have been developed. The reaction gave the corresponding Michael adducts of multifunctional cyclohexenol derivatives with three
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。
Asymmetric Organocatalytic [4 + 1] Annulations Involving a Polarity Reversal Process: A Tandem Catalytic Approach to Highly Functionalized Spiropyrazolone Derivatives
A tandemcatalytic strategy for the asymmetric synthesis of spirocyclopentanone pyrazolones bearing threecontiguousstereocenters and two quaternary carbons with good stereoselectivities has been developed. This strategy, using pyrazolones as efficient C1 synthons and involving a polarity reversal process, not only overcame the energy barrier of the dearomatization process but also avoided nucleophilic
A method for the enantioselective construction of hydrocarbazole skeletons through dearomative [4 + 2] annulation of 3-nitroindoles with Nazarov reagents is reported. The reactions use multiple hydrogen-bonding bifunctional thiourea as catalyst and are highly diastereo- and enantioselective (up to >20:1 dr and >99% ee). The protocol was demonstrated by preparative-scale experiment and the versatile
Organocatalytic Asymmetric Formal [4 + 2] Cycloaddition for the Synthesis of Spiro[4-cyclohexanone-1,3′-oxindoline] Derivatives in High Optical Purity
作者:Qiang Wei、Liu-Zhu Gong
DOI:10.1021/ol100020v
日期:2010.3.5
A bifunctional organocatalytic asymmetric formal [4 + 2] cycloaddition reaction of Nazarov reagents and methyleneindolinones afforded spiro[4-cyclohexanone-1,3′-oxindoline] derivatives with excellent enantioselectivity (up to 98% ee).