Abstract: A variety of domino and multicomponent reactions were developed which include domino Knoevenagel / hetero-Diels-Alder reactions, the combination of Knoevenagel reactions with [3+2] cycloadditions of nitrogen ylides, domino Knoevenagel / enamine cyclization reactions, formal [3+3] cyclizations of pyridinium salts, [3+3] cyclizations of thioxindoles with fluoroaroyl chlorides, cyclizations of heterocyclic enamines with diimines and triazines, domino [4+2] / retro [4+2] reactions, formal [3+3] cyclizations of 2-ethynylpyridines with enones, reaction of trifluoromethyl-substituted 1,3-diketones with lithiated alkynes and formal [3+2] cyclizations of 2,3-dihalopyridines with imines. These reactions provide a convenient access to various drug-like compounds.

Review: Peter Langer, Eur. J. Org. Chem. 2024, https://doi.org/10.1002/ejoc.202400153.

Period of investigation: 2009 - Today

Keywords: domino reactions; cyclizations; iminium salts

Abstract: Domino reactions of heterocyclic enamines with chromone derivatives provide a convenient access to a great variety of annulated heterocyclic ring systems. The course of the reaction depends on the type of substituent located at position 3 of the chromone.

Review: Synlett 2022, 33, 207–223.

Period of investigation: 2009 - Today

Keywords: heterocyclic enamines; cyclizations; heterocycles; chromones

Abstract: Domino reactions of chromones with activated carbonyl compounds, such as dimethyl acetone-1,3-dicarboxylate and 1,3-diphenylacetone, and with 1,3-bis(silyloxy)-1,3-butadienes, electroneutral equivalents of 1,3-dicarbonyl dianions, allow for a convenient synthesis of a great variety of products. The regioselectivity and course of the reaction depends on the substituent located at carbon C3 of the chromone moiety and also on the type of nucleophile employed.

Review: Peter Langer, Beilstein J. Org. Chem. 2024, under revision.

Period of investigation: 2002 - Today

Keywords: domino reactions; chromones; 1,3-dicarbonyl compounds

Abstract: 4-(Silyloxy)benzopyrylium triflates can be readily generated in situ by reaction of chromones with trialkylsilyl-trifluoromethanesulfonate. Domino reactions of bis(silyl enol ethers) with such benzopyrylium triflates – derived from chromones, 3-cyanochromones and 3-formylchromones – allow for an efficient synthesis of a variety of carbo- and heterocycles.

Review: Synlett 2007, 1016-1025.

Period of investigation: 2001 - 2011

Keywords: silyl enol ethers; chromones; heterocycles

Abstract: The combination of Heck reactions with 6p-electrocyclization reactions allows for the synthesis of a variety of various benzoannulated heterocycles.

Review: Synlett 2012, 23, 2735-2745.

Period of investigation: 2008 - 2013

Keywords: Pd-catalysis; heterocycles; domino reactions

Abstract: 2-Isothiocyanatobenzonitrile (ITCB) and isocyanatobenzonitrile (ICB) represent versatile synthetic building blocks containing a nitrile and an isothiocyanate or an isocyanate function, respectively. Domino reactions of ITCB and ICB provide a convenient access to a variety of pharmacologically important heterocycles.

Review: Curr. Org. Chem. 2009, 13, 955-964.

Period of investigation: 2002 – 2009

Keywords: domino reactions; cyclizations; heterocycles