Tanmoy Chanda

InCl3‐Driven Regioselective Synthesis of Functionalized/Annulated Quinolines: Scope and Limitations

The efficient, regioselective synthesis of functionalized/annulated quinolines was achieved by the coupling of 2-aminoaryl ketones with alkynes/active methylenes/α-oxoketene dithioacetals promoted by InCl(3) in refluxing acetonitrile as well as under solvent-free conditions in excellent yields. This transformation presumably proceeded through the hydroamination-hydroarylation of alkynes, and the Friedländer annulation of active methylene compounds and α-oxoketene dithioacetals with 2-aminoarylketones. In addition, simple reductive and oxidative cyclization of 2-nitrobenzaldehyde and 2-aminobenzylalcohol, respectively, afforded substituted quinolines. Systematic optimization of the reaction parameters allowed us to identify two-component coupling (2CC) conditions that were tolerant of a wide range of functional groups, thereby providing densely functionalized/annulated quinolines. This approach tolerates the synthesis of various bioactive quinoline frameworks from the same 2-aminoarylketones under mild conditions, thus making this strategy highly useful in diversity-oriented synthesis (DOS). The scope and limitations of the alkyne-, activated methylene-, and α-oxoketene dithioacetal components on the reaction were also investigated.

β-Oxodithioesters: a new frontier for diverse heterocyclic architectures

Utilization of the fascinating properties of β-oxodithioesters as building blocks in heterocyclic frameworks was started a few decades ago. Its similarity and dissimilarity with β-ketoesters in terms of its synthesis or as a substrate towards synthesis makes it an interesting and emerging field of synthetic organic chemistry. Tuning of catalysts and counter substrates towards selective utilization of its multiple reacting sites was summarized in the following discussion. A diverse range of monocyclic and polycyclic heterocycles with several different heteroatoms is plotted in an easy and reader friendly manner.

Palladium catalyzed oxidative coupling of α-enolic dithioesters: a new entry to 3,4,5-trisubstituted 1,2-dithioles via a double activation strategy.

An operationally simple, facile, and convenient one-pot straightforward method for the construction of 3,4,5-trisubstituted 1,2-dithioles has been explored and developed via palladium catalyzed self-coupling of α-enolic dithioesters for the first time. Pd(0) efficiently catalyzes the activation and cleavage of S-H and C-S bonds to achieve cascade coupling, which results in the concomitant formation of new S-S and C-C bonds. Optimization data, substrate scope, and mechanistic insights are discussed.

CuSO4–D-glucose, an inexpensive and eco-efficient catalytic system: direct access to diverse quinolines through modified Friedländer approach involving SNAr/reduction/annulation cascade in one pot

A highly efficient and scalable multicomponent domino reaction for the synthesis of functionalized/annulated quinolines is devised directly from 2-bromoaromatic aldehydes/ketones in H2O–EtOH mixture for the first time. The key to this reaction is the use of an air-stable, eco-efficient and inexpensive CuSO4–D-glucose catalyst system, which is able to catalyze multiple transformations in one pot. The approach is carbon-economic and relies on sequential SNAr/reduction/Friedlander annulation steps, forming C–C and C–N bonds by cleavage of the Csp2–Br bond in a single synthetic operation. The reaction has a broad substrate scope and affords products in good to excellent yields.

Organocatalyzed straightforward synthesis of highly fluorescent 3,5-disubstituted 2,6-dicyanoanilines via domino annulation of α-enolicdithioesters with malononitrile

Piperidine mediated a robust, efficient, and selective one-pot synthesis of previously inaccessible and highly fluorescent 3,5-disubstituted 2,6-dicyanoanilines. This was achieved via the domino carboannulation of α-enolicdithioesters with malononitrile by dehydrative CO/CS bond functionalization. It is presumed that the domino sequence includes base promoted nucleophilic addition, Knoevenagel condensation and ANRORC (addition of nucleophile/ring opening/ring closure) steps. The screening for optical properties identified a strong blue emission with high fluorescence quantum yields.

Developments toward the synthesis and application of 3-hydroxyindanones.

3-Hydroxyindanone is an important scaffold in many natural products, biologically active compounds, and functional materials. This review provides a comprehensive overview of the construction of 3-hydroxyindanone derivatives and their applications towards pharmaceutically promising drug candidates. The total synthesis of the complex natural products containing this simple core is discussed. The highlights of the literature from 1948 to 2015 are comprised.