Synthesis of Triazolo Isoquinolines and Isochromenes from 2-Alkynylbenzaldehyde via Domino Reactions under Transition-Metal-Free Conditions
摘要:
We describe two simple straightforward syntheses of triazolo isoquinolines (3) and isochromenes (7) from 2-alkynylbenzaldehydes (1) as a common synthon. The synthetic strategy for 3 involves formation of the (E)-1-(2-nitrovinyl)-2-(alkynyl)benzene species 2 via condensation of synthon 1 with nitromethane followed by a [3 + 2] cycloaddition/extrusion of the nitro group/regioselective 6-endo cyclization domino sequence. In yet another strategy, the synthon 1 was condensed with nitromethane followed by electrophilic iodo cyclization of the resulting 2-nitro-1-(2-(alkynyl)phenyl)ethanol (6) to furnish iodo isochromene derivatives. The salient feature of the above two strategies involves formation of the corresponding heterocycles under metal-free conditions in good yields.
Metal-Free Decarboxylative Cyclization/Ring Expansion: Construction of Five-, Six-, and Seven-Membered Heterocycles from 2-Alkynyl Benzaldehydes and Cyclic Amino Acids
A one pot synthesis of 1H‐benzo[g]indoles, tetrahydrobenzo[h]quinolines, and naphtho[1,2‐b]azepines from 2‐alkynyl benzaldehydes and cyclic amino acids is reported. The salient feature of the strategy involves formation of three new bonds (one CN and two CC bonds) by a metal‐free decarboxylation/cyclization/one‐carbon ring expansion sequence in one pot.
Organocatalytic Asymmetric Multicomponent Cascade Reaction for the Synthesis of Contiguously Substituted Tetrahydronaphthols
作者:Yidong Liu、Joseph A. Izzo、David McLeod、Sebastijan Ričko、Esben B. Svenningsen、Thomas B. Poulsen、Karl Anker Jørgensen
DOI:10.1021/jacs.1c03923
日期:2021.6.2
unique, highly reactive, aromatic intermediates which are largely unexplored in asymmetric catalysis despite their high potential synthetic utility. In this study, an organocatalytic asymmetric multicomponent cascade via dienamine catalysis, involving a cycloaddition, a nucleophilic addition, and a ring-opening reaction, is disclosed. The reaction furnishes chiral tetrahydronaphthols containingfour contiguous
can be selectively controlled toward the formation of two families of skeletally diverse benzo[g]indoles and 1-naphthols under mild conditions. Silver salt was found to efficiently promote indole annulation to give multifunctional benzo[g]indoles with the installation of two sulfonyl groups into the indole ring via N–S and N–F bond cleavage of NFSI, whereas NBS and NCS-mediated benzannulations occurred
已经建立了苯连接的烯-炔的新型碳-碳三键断裂和重排反应。在温和的条件下,可以选择性地控制反应,以形成两个不同骨架的苯并[ g ]吲哚和1-萘酚。发现银盐可有效促进吲哚环化,并通过NFSI的N–S和N–F键裂解,在吲哚环中安装两个磺酰基,从而形成多功能的苯并[ g ]吲哚,而NBS和NCS介导的苯环发生在二卤代1-萘酚的形成。
Iodine-mediated electrophilic tandem cyclization of 2-alkynylbenzaldehydes with anthranilic acid leading to 1,2-dihydroisoquinoline-fused benzoxazinones
作者:Shashikant U. Dighe、Sanjay Batra
DOI:10.1016/j.tet.2013.08.086
日期:2013.11
An efficient iodine-mediated electrophilic tandem cyclization of substituted 2-alkynylbenzaldehydes with anthranilic acids under basic medium leading to iodo-1,2-dihydroisoquinoline-fused benzoxazinones is presented. Success of the protocol for the reaction of substituted 2-alkynylbenzaldehydes with 2-aminobenzamides to furnish isoquinoline-fused quinazolinones is also described.
Tetrabutylammonium Bromide Catalyzed Tandem Addition/Cyclization of o-Aralkynylaryl Aldehydes with Trimethyl(trifluoromethyl)silane: Synthesis of Trifluoromethyl Group Containing Phthalans
A tetrabutylammonium bromide catalyzed trifluoromethylation/cyclization reaction of o -aralkynylaryl aldehydes with trimethyl(trifluoromethyl)silane and cesium fluoride has been developed. A variety of 1-alkylidene-3-(trifluoromethyl)phthalans were prepared in moderate to excellent yields by tandem nucleophilic addition and cyclization.