NHC-Catalyzed Reaction of Enals with Hydroxy Chalcones: Diastereoselective Synthesis of Functionalized Coumarins
作者:Anup Bhunia、Atanu Patra、Vedavati G. Puranik、Akkattu T. Biju
DOI:10.1021/ol400562z
日期:2013.4.5
The N-heterocyclic carbene-catalyzed annulation of enals with 2′-hydroxy chalcones afford cyclopentane-fused coumarin derivatives with an excellent level of diastereocontrol. The reaction tolerates a broad range of functional groups; 25 examples are given, and a preliminary mechanistic investigation is provided.
Enantioselective synthesis of tetra-substituted tetralines and tetrahydro-indolizines by NHC-catalyzed azolium–enolate cascade
作者:Arghya Ghosh、Shilpa Barik、Sayan Shee、Akkattu T. Biju
DOI:10.1039/d1cc03165a
日期:——
NHC-catalyzed cascade reaction of enals with suitably substituted β-(hetero)aryl enones allowing the enantioselective synthesis of tetra-substituted tetralines and tetrahydro indolizines is presented. The catalytically generated chiral α,β-unsaturated acylazoliums fromenals under oxidative conditions reacted in a Michael–Michael-lactonization sequence to form the tricyclic δ-lactone products bearing
Enantioselective N-Heterocyclic Carbene-Catalyzed Cascade Reaction for the Synthesis of Pyrroloquinolines via N–H Functionalization of Indoles
作者:Subrata Mukherjee、Sayan Shee、Thomas Poisson、Tatiana Besset、Akkattu T. Biju
DOI:10.1021/acs.orglett.8b02820
日期:2018.11.16
Functionalization of the indole N–H bond for enantioselectivesynthesis of biologically important pyrroloquinoline derivatives has been reported under oxidative N-heterocycliccarbenecatalysis conditions. The interception of catalytically generated chiral α,β-unsaturated acylazoliums with the indole derivatives proceeds in an aza-Michael/Michael/lactonization sequence to deliver the pyrroloquinoline
据报道,在氧化的N-杂环卡宾催化条件下,吲哚NH键可用于对映体选择性合成生物学上重要的吡咯并喹啉衍生物。吲哚衍生物对催化生成的手性α,β-不饱和酰基acy的截获以aza-Michael / Michael /内酯化顺序进行,从而以高收率,非对映选择性和对映选择性传递吡咯并喹啉衍生物。在极性非质子溶剂中观察到的反应性和选择性的同时提高是值得注意的。
N-Heterocyclic Carbene-Catalyzed Michael–Michael–Lactonization Cascade for the Enantioselective Synthesis of Tricyclic δ-Lactones
作者:Subrata Mukherjee、Arghya Ghosh、Udaya Kiran Marelli、Akkattu T. Biju
DOI:10.1021/acs.orglett.8b00998
日期:2018.5.18
Enantioselective synthesis of tricyclic δ-lactones with three contiguous stereocenters has been demonstrated by the N-heterocyclic carbene (NHC)-catalyzed functionalization of benzylic C(sp3)–H bonds. The NHC-catalyzed reaction of enals with dinitrotoluene derivatives under oxidative conditions proceeds via the chiral α,β-unsaturated acylazoliums and produces the δ-lactones in good yields and excellent diastereoselectivity
Synthesis of Functionalized Dihydrocoumarins by NHC-Catalyzed [3 + 3] Annulation of Enals with 2-Substituted Naphthoquinones
作者:Sayan Shee、Soumen Barik、Arghya Ghosh、Akkattu T. Biju
DOI:10.1021/acs.orglett.1c03059
日期:2021.10.15
The [3 + 3] annulation of α,β-unsaturated aldehydes with 2-substituted 1,4-naphthoquinones allowing the facile synthesis of functionalized dihydrocoumarins catalyzed by N-heterocyclic carbene (NHC) is reported. The initially formed NHC-homoenolates underwent an efficient Michael–isomerization–lactonization cascade to furnish the products. Preliminary studies on mechanism shed light on the homoenolate