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。
Catalytic Asymmetric Conjugate Arylation of γ,δ-Unsaturated β-Dicarbonyl Compounds
asymmetric conjugate addition to γ,δ-unsaturated β-dicarbonylcompounds was developed. With a chiral diene–rhodium(I) μ-chloro dimer as the catalyst in toluene/H2O, asymmetric conjugate arylation of γ,δ-unsaturated β-dicarbonylcompounds with arylboronic acids proceeded in high efficiency with excellent enantioselectivities. The generated β-dicarbonyl products are versatile chiral synthons, which can
研发了向γ,δ-不饱和β-二羰基化合物中的第一个催化不对称共轭加成物。用手性二烯-铑(I)μ-氯二聚体作为甲苯/ H 2 O的催化剂,γ,δ-不饱和β-二羰基化合物与芳基硼酸的不对称共轭芳基化反应高效进行,具有出色的对映选择性。生成的β-二羰基产物是通用的手性合成子,可以容易地转化为多种重要的手性结构。
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