在DABCO促进的MW辐射下,在纯净条件下,开发了5/6元环状氨基磺酸亚胺与各种β,γ-不饱和α-酮羰基化合物的高效,无溶剂,生态友好的多米诺反应,该反应是由DABCO促进的,作为固体有机碱用于快速构建新型的高密度官能化的吡啶甲酸类化合物。这种有趣的无金属溶剂策略可在芳基环上提供多种有用的功能,并能在较短的时间间隔(20-40分钟)内,将上述氮杂杂环化合物的收率很好地提高。通过我们独特的方法成功合成了具有生物学前途的咪唑并[1,2- a ]吡啶。
Reactions of pyruvates: organocatalytic synthesis of functionalized dihydropyrans in one pot and further transformations to functionalized carbocycles and heterocycles
Tertiary Amine Mediated Tandem Cross-Rauhut-Currier/Acetalization Reactions: Access to Functionalized Spiro-3,4-Dihydropyrans
作者:Weijun Yao、Yihua Wu、Gang Wang、Yiping Zhang、Cheng Ma
DOI:10.1002/anie.200905091
日期:2009.12.14
γ‐Proton transfer furnished the highly selective title reaction in which cyclic β‐haloenals 1 react with β,γ‐unsaturated α‐ketoesters 2 to generate functionalized spiro‐3,4‐dihydro‐2H‐pyrans 3 having an α‐quaternary carbon center and an adjacent vinyl halide group in skeleton. DBU=1,8‐diazabicyclo[5.4.0]undec‐7‐ene, Tos=4‐toluenesulfonyl.
Highly Enantioselective Friedel-Crafts Reaction of 4,7-Dihydroindoles with β,γ-Unsaturated α-Keto Esters by Chiral Brønsted Acids
作者:Mi Zeng、Qiang Kang、Qing-Li He、Shu-Li You
DOI:10.1002/adsc.200800523
日期:2008.10.6
A highly efficient Friedel–Craftsreaction of 4,7-dihydroindoles with β,γ-unsaturatedα-ketoesters by a chiral N-triflyl phosphoramide was realized, affording the 2-substituted 4,7-dihydroindoles with up to 98% ee for a wide range of substrates. The Friedel–Crafts alkylation together with a subsequent oxidation of the product with p-benzoquinone led to a 2-alkylated indole derivative in 98% ee.
Highly stereoselective construction of tetrahydroquinolines via cascade aza-Michael-Michael reaction: Formal [4+2] cycloaddition of β,γ-unsaturated α-ketoesters with 2-aminochalcones
作者:Cong Duan、Yongqi Yao、Ling Ye、Zhichuan Shi、Zhigang Zhao、Xuefeng Li
DOI:10.1016/j.tet.2018.10.053
日期:2018.12
An efficient cascade aza-Michael-Michael sequence for the preparation of tetrahydroquinolines has been established. Three contiguous stereogenic centers are created with high levels of enantioselectivities (79–99% ee) and exclusive diastereoselectivities in the presence of a bifunctional squaramide. This approach is compatible with a broad range of β,γ-unsaturated α-ketoesters and 2-aminochalcones
An organocatalyticenantioselectiveMichaeladdition of 2-hydroxy-1,4-naphthoquinone to β,γ-unsaturatedα-oxoesters has been developed. The process was promoted by bifunctional chiral amine derived squaramides according to a hydrogen-bonding mediated activation mechanism and afforded the chiral adducts in high yields (up to 88 %) and excellent enantioselectivity (up to 98 % ee) under mild conditions
Chiral Squaramides as Highly Enantioselective Catalysts for Michael Addition Reactions of 4-Hydroxycoumarins and 4-Hydroxypyrone to β,γ-Unsaturated α-Keto Esters
Distance brings forth beauty: The first highlyenantioselectiveorganocatalyticMichaeladdition of 4‐hydroxycoumarins and the analogous 4‐hydroxy‐6‐methyl‐2‐pyrone to β,γ‐unsaturated α‐keto esters by using chiral squaramides as the organocatalysts is disclosed. The efficiency of the process is attributed to the hydrogen‐bonding activation (see scheme).