Unusual Reactivity of Isoquinolinones Generated by Silver-Catalyzed Cycloisomerizations of Imines Derived from ortho-Alkynylsalicylaldehydes

Base-Promoted Synthesis of Isoquinolines through a Tandem Reaction of 2-Methyl-arylaldehydes and Nitriles

A convenient method for preparing 3-aryl isoquinolines via a base-promoted tandem reaction is presented. Simply combining commercially available 2-methyl-arylaldehydes, benzonitriles, NaN(SiMe3)2, and Cs2CO3 enabled the synthesis of a variety of isoquinolines (23 examples, ≤90% yield). Among the syntheses of isoquinolines, the transition metal-free method described here is straightforward, practical, and operationally simple.

Alkaline-Metal-Promoted Divergent Synthesis of 1-Aminoisoquinolines and Isoquinolines

Alkaline-metal-promoted divergent syntheses of 1-aminoisoquinolines and isoquinolines have been reported involving 2-methylaryl aldehydes, nitriles, and LiN(SiMe3)2 as reactants. In addition, the three-component reaction of 2-methylaryl nitriles, aldehydes, and LiN(SiMe3)2 has been developed to furnish 1-aminoisoquinolines. This protocol features readily available starting materials, excellent chemoselectivity, broad substrate scope, and satisfactory yields.

Recent advances in the application of alkynes in multicomponent reactions

Alkynes have two active positions to carry out chemical reactions: C[triple bond, length as m-dash]C and C-H. These two positions are involved and activated in different reactions using different reagents. In this study, we investigated the reactions of alkynes that are involved in multi-component reactions through the C-C and C-H positions and examined the progress and gaps of each reaction by carefully studying the mechanism of the reactions. Firstly, we investigated and analyzed the reactions involving the C[triple bond, length as m-dash]C position of alkynes, including the reactions between derivatives of alkynes with RN3, sulfur compounds (RSO2R', DMSO, S8, DABCO(SO2)2 and DABSO), barbituric acids, aldehydes and amines, COOH, α-diazoesters or ketones, and isocyanides. Then, we examined and analyzed the important reactions involving the C-H position of alkynes and the progress and gaps in these reactions, including the reaction between alkyne derivatives with amines and aldehydes for the synthesis of propargylamines, the reaction between alkynes with CO2 and the reaction between alkynes with CO.

Stereoselective synthesis of fused-, spiro- and bridged heterocycles via cyclization of isoquinolinium salts: A recent update

Isoquinoline and its derivatives are ubiquitous in natural alkaloids, synthetic materials and pharmaceuticals with broad spectrum of biological activities. In particular, isoquinolinium salts are important in organic synthesis because they...

Cocatalyst-controlled divergent cascade cycloaddition reaction of arylalkynols and dioxopyrrolidienes: access to spiroketals and oxa-bridged eight-membered cyclic ethers

A cocatalyst-controlled divergent cascade cycloaddition reaction was developed for the synthesis of two different complex oxygen-containing heterocyclic compounds from arylalkynols and dioxopyrrolidienes in the presence of Au(i) catalyst.

AgNTf2-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

A formal [3 + 2] cycloaddition between ynamides and unprotected isoxazol-5-amines has been developed in the presence of catalytic AgNTf2 in an open flask. By the protocol, a variety of functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives can be obtained in up to 99% yield. The reaction mechanism might involve the generation of an unusual α-imino silver carbene intermediate (or a silver-stabilized carbocation) and subsequent cyclization/isomerization to build the significant pyrrole-3-carboxamide motif. The reaction features the use of an inexpensive catalyst, simple reaction conditions, simple work-up without column chromatographic purification for most of products and high yields.