Stable azomethine imines having a 3,4-dihydroisoquinoline fragment and their cycloaddition to N-arylmaleimides
摘要:
Aroylation of 5,6,8,8a,13,14,16,16a-octahydro[1,2,4,5]tetrazino[6,1-a:3,4-a']diisoquinoline or 1,3,4,8b-tetrahydro[1,2]diazireno[3,1-a]isoquinoline, as well as reactions of 2-(2-bromoethyl)benzaldehyde with aroylhydrazines followed by treatment with triethylamine, led to the formation of stable azomethine imines, aroyl(3,4-dihydroisoquinolinium-2-yl)azanides. 1,3-Dipolar cycloaddition of the latter to N-mesitylmaleimide was stereoselective: the ratio of the trans- and cis-adducts was similar to(3-7): 1, the former prevailing. The reactions with N-arylmaleimides having no ortho-substituents in the aryl group gave the corresponding cis-adducts as the major products [trans/cis ratio similar to 1: (2.5-10)].
with azomethineimines has successfully been developed under mild reaction conditions, affording biologically interesting tetrahydropyrazoloisoquinoline derivatives in high to excellent yields and with excellent stereoselectivity. The reaction follows a tandem [3+2] cycloaddition/allylation/elimination of AcOH pathway. Allenyl carbinol acetates also reacted well with in situ generated azomethine imine
The thermal1,3-dipolarcycloadditions of 4-acetoxyallenoates 1 with various dipoles have been reported. When azomethine imines and nitrones are used as the 1,3-dipole partner, the corresponding reactions afford 2,3-dihydropyrazole and 2,3-dihydroisoxazole derivatives, respectively. These reactions might proceed via a thermal1,3-dipolarcycloaddition and the subsequent elimination of HOAc. In addition
Cross 1,3-dipolar cycloadditions of <i>C</i>,<i>N</i>-cyclic azomethine imines with an <i>N</i>-benzyl azomethine ylide: facile access to fused tricyclic 1,2,4-hexahydrotriazines
A cross 1,3-dipolarcycloaddition of two different ylides between C,N-cyclicazomethineimines with an in situ-generated nonstabilized azomethine ylide from an N-benzyl precursor was realized. The reactions afforded a clean and facile access to diverse fused tricyclic 1,2,4-hexahydrotriazines in high yields (up to 96%). The chemical structures of the typical compounds were confirmed by X-ray single-crystal
Chemodivergent 1,3-Dipolar Cycloadditions of <i>C</i>,<i>N</i>-Cyclic Azomethine Imines with γ-Sulfonamido-α,β-Unsaturated Ketones to Synthesize Tricyclic Dinitrogen-Fused Heterocycles
作者:Jaeeun No、Young Jae Yun、Sung-Gon Kim
DOI:10.1021/acs.joc.2c02949
日期:2023.2.3
1,3-Dipolarcycloadditions of C,N-cyclic azomethine imines with γ-NHTs-α,β-unsaturated ketones were developed to synthesize tricyclic dinitrogen-fused heterocycles. Highly functionalized tricyclic tetrahydroisoquinolines were readily obtained in good to high yields in the [3 + 2]-cycloaddition reaction of N-Bz-protected C,N-cyclic azomethine imines with γ-NHTs-α,β-unsaturated ketones undermild reaction
开发了C , N -环偶氮亚胺与 γ-NHTs-α,β-不饱和酮的1,3-偶极环加成以合成三环双氮稠合杂环。在N -Bz 保护的C , N -环偶氮甲亚胺与 γ-NHTs-α,β-不饱和酮的 [3 + 2]-环加成反应中,在温和的反应条件下,很容易以高收率获得高度官能化的三环四氢异喹啉. 此外,DABCO 催化的N -Ts 保护的C , N的环加成反应-环状偶氮甲亚胺与 γ-NHTs-α,β-不饱和酮裂解甲苯磺酰基是合成四氢吡唑并 [5,1- a ] 异喹啉的简便途径,产率高,非对映选择性好。