selective dehydrohalogenation to form alpha-haloacrylate analogues. A variety of alpha-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of alpha-bromoacrolein and alpha-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures
Carbenes ring true: N‐Heterocycliccarbene (NHC) catalyzed reactions of α‐bromo‐α,β‐unsaturated aldehydes/α,β‐dibromoaldehydes with 1,3‐dinucleophilic reagents, such as 1,3‐dicarbonyl compounds, β‐enamino ketones, and β‐enamino esters through umpolung processes gave functionalized 3,4‐dihydropyranones and 3,4‐dihydropyridinones (see scheme). The availability of the starting materials, lack of external
Synthesis of Dihydropyridinone-Fused Indoles and α-Carbolines via N-Heterocyclic Carbene-Catalyzed [3 + 3] Annulation of Indolin-2-imines and Bromoenals
作者:Liang Yi、Yuyang Zhang、Zhao-Fei Zhang、Dequn Sun、Song Ye
DOI:10.1021/acs.orglett.7b00820
日期:2017.5.5
The N-heterocyclic carbene catalyzed [3 + 3] annulation of indolin-2-imines and bromoenals was developed to give dihydropyridinone-fused indoles in good to high yields, which were transformed to α-carbolines with different 2-subsituents by a process of dehydrogenation, tosylation, and palladium catalyzed C–C or C–N coupling reaction.
A facile synthesis of tetrahydroimidazo[1,2-a]pyridines and tetrahydrobenzo[b]imidazo[1,2,3-ij][1,8]naphthyridines through NHC-catalyzed cascade annulations
A new efficient approach for the synthesis of tetrahydroimidazo[1,2-a]pyridines and tetrahydrobenzo[b]imidazo[1,2,3-ij][1,8]naphthyridines with biological significance was successfully developed through a NHC-catalyzed cascade C–C bond and C–N bond formation process. This new alternative approach for the assembly of these multi-functionalized nitrogen bridgehead-fused heterocycles features mild conditions
通过NHC催化的级联反应成功开发了一种新的高效合成四氢咪唑并[1,2- a ]吡啶和四氢苯并[ b ]咪唑并[1,2,3- ij ] [1,8]萘啶的新方法C–C键和C–N键的形成过程。组装这些多功能氮桥头稠合杂环的这种新的替代方法具有温和的条件,中等至高收率和操作简便性。
N-Heterocyclic Carbene-Catalyzed [3+3] Annulation of Indoline-2-thiones with Bromoenals: Synthesis of Indolo[2,3-<i>b</i>]dihydrothiopyranones
作者:Liang Yi、Kun-Quan Chen、Zhi-Qin Liang、De-Qun Sun、Song Ye
DOI:10.1002/adsc.201600726
日期:2017.1.4
The N‐heterocyclic carbene‐catalyzed [3+3] annulation of indoline‐2‐thiones and bromoenals has been developed, giving the corresponding indolo[2,3‐b]dihydrothiopyranones in high yields.
已开发出N-杂环卡宾催化的吲哚-2-硫酮和溴代烯环化[3 + 3]环化反应,从而以高收率得到了相应的吲哚[2,3- b ]二氢硫代吡喃酮。