Green Protocols in Heterocycle Syntheses via 1,3-Dipolar Cycloadditions

The [3 + 3]-Cycloaddition Alternative for Heterocycle Syntheses: Catalytically Generated Metalloenolcarbenes as Dipolar Adducts

The combination of two or more unsaturated structural units to form cyclic organic compounds is commonly referred to as cycloaddition, and the combination of two unsaturated structural units that forms a six-membered ring is formally either a [5 + 1]-, [4 + 2]-, [2 + 2 + 2]-, or [3 + 3]-cycloaddition. Occurring as concerted or stepwise processes, cycloaddition reactions are among the most usefu...

Iridium–catalyzed 1,3–dipolar cycloadditions

1,3–Dipolar cycloaddition reactions (DCR) are atom–economic processes that permit the construction of heterocycles. Their enantioselective versions allow for the creation of up to four adjacent chiral centers in a concerted fashion. In particular, well–defined half–sandwich iridium (III) catalysts have been applied to the DCR between enals or methacrylonitrile with nitrones. Excellent yield and...

Probing heterocycle conformation with residual dipolar couplings.

Residual dipolar couplings (RDCs) obtained in a stretched polydimethylsiloxane gel are applied to determine the 7-membered ring conformation in a 2-phenyl-3-benzazepine derivative, and to simultaneously assign all methylene proton pairs using only (1)D(CH) RDCs and DFT molecular modelling data.

A Universal Isocyanide for Diverse Heterocycle Syntheses

Novel scaffolds are of uttermost importance for the discovery of functional material. Three different heterocyclic scaffolds easily accessible from isocyanoacetaldehyde dimethylacetal 1 by multicomponent reaction (MCR) are described. They can be efficiently synthesized by a Ugi tetrazole multicomponent reaction of 1. We discuss the synthesis, 3D structures, and other physicochemical properties.

Enantioselective copper-catalyzed 1,3-dipolar cycloadditions.