meldrum's acid, 2'5-diphenyl-1'3-dioxane-4'6-dione, was produced by [2+2] cycloadditions of the (chlorocarbony1)phenylketene with benzaldehyde. acid hydrolysis of the meldrum's acid regenerated benzaldehyde and also yielded phenylacetic acid as the final product

Biohybrid amphiphiles have been prepared from terminal azide functionalised polystyrene and an alkyne functionalised peptide or protein via a Cu(I) catalysed Huisgen [3 + 2] dipolar cycloaddition reaction.

The reaction of 17,17-dichloro-androst-16(E)-chloromethylene with secondary amine base afforded substitution products exocyclic D-ring ketones, in contrast to the alkaline which cleaved steroidal des-D formyl alkyne. alkyne was employed prepare annulated isoxazolo steroid via 1,3-dipolar nitrile oxide cycloaddition reaction.

Electron-rich dienes have revolutionized the synthesis of complex compounds since the discovery of the legendary Diels-Alder cycloaddition reaction. This highly efficient bond-forming process has served as a fundamental strategy to assemble many structurally formidable molecules. Amino silyloxy butadienes are arguably the most reactive diene species that are isolable and bottleable. Since the p...

Intramolecular cycloadditions between cyclobutadiene and olefins can provide highly functionalized cyclobutene-containing products. The outcome of the reaction depends on the nature of the tether connecting the two reactive partners in the cycloaddition. Electronically unactivated olefins attached to cyclobutadiene through a three-atom, heteroatom-containing tether yield successfully the desire...

The intramolecular Diels-Alder reactions of cycloalkenones and terminal dienes occur with high endo stereoselectivity, both thermally and under Lewis-acidic conditions. Through computations, we show that steric repulsion and tether conformation govern the selectivity of the reaction, and incorporation of either BF3 or α-halogenation increases the rate of cycloaddition. With a longer tether, iso...

The first intramolecular [4 + 3] cycloaddition reaction using nitrogen-stabilized chiral oxyallyl cations that are tethered to furan or diene through the nitrogen atom is described here. Formation of these nitrogen-stabilized chiral oxyallyl cations is achieved by a chemoselective epoxidation of chiral allenamides via syringe pump addition of dimethyl dioxirane. The ensuing cycloaddition can be...

tropane alkaloids, and consequently there is an increasing interest in their potential pharmaceutical use, particularly against cocaine abuse. Compelled by the interesting biological activities of 8oxatropanes, many groups have embarked on the search for new methodologies to construct this bicyclic structure. For example, Molander and co-workers have reported a Lewis acid promoted double allyla...

A highly stereoselective desymmetrization reaction of δ,δ-diaryl-α-diazo-β-ketoesters catalyzed by chiral dirhodium carboxylates forms aromatic cycloaddition products in up to 97% ee.

The first example of a regioselective and organocatalyzed 1,3-dipolar cycloaddition reaction between conjugated alkynoates and nitrones "on water" is described.