Tetrahydroisoquinoline-3-carboxylic acid derivatives are prepared via a [2 + 2 + 2] cycloaddition reaction as a key step using Wilkinson's and CpCo(CO)2 catalysts.

1- (Phthalazin-l'-yl-amino)-3-chloro-4-aryl-4H-(4o-rm ethyl)-2-azetidinones (3) were prepared by cycloaddition of-methyl substituted benzal hydrazinophthalazine (2) with chloro acetylchloride. The hydrazone (2) was synthesised by the condensation of 1- hydrazinophthalazine (1) with substituted aromatic aldehydes, ketones 7 acetophenones. 1- Hydrazinophthalazine was prepared from the phthal...

The aryne [3 + 2] cycloaddition process with pyridinium imides breaks the aromaticity of the pyridine ring. By equipping the imide nitrogen with a sulfonyl group, the intermediate readily eliminates a sulfinate anion to restore the aromaticity, leading to the formation of pyrido[1,2-b]indazoles. The scope and limitation of this reaction are discussed. As an extension of this chemistry, N-tosyli...

Cycloaddition reactions represent one of the most powerful processes in organic chemistry. The most common types of cycloaddition reactions are the Diels-Alder (DA) and the 1,3-dipolar cycloaddition reactions (1,3-DCs) which lead to five and six membered rings, respectively. In our ongoing efforts to contribute to the understanding of DA and 1,3-DCs; we studied the following using the B3LYP/6-3...

The 1,3-dipolar cycloaddition of azides and activated alkynes has been used for site-selective labeling of biomolecules in vitro and in vivo. While copper catalysis has been widely employed to activate terminal alkynes for [3 + 2] cycloaddition, this method, often termed "click chemistry", is currently incompatible with living systems because of the toxicity of the metal. We recently reported a...

An unexpected and interesting intramolecular side reaction occurred during the attempted synthesis of glycosyl cyanides upon treatment of 1-O-acetyl-3-azido-3-deoxyallose derivatives with TMSCN and different Lewis acids. Exo-1,2-O-cyanoalkylidene derivatives formed by neighboring group participation and attack of cyanide underwent, after Lewis-acid mediated isomerization to the endo-isomer, int...

In the title compound, C(11)H(11)N(3)O(2), prepared by the [3+2] cycloaddition reaction of benzyl azide with methyl propiolate, the dihedral angle between the ring planes is 67.87 (11)°.

Diazo(trimethylsilyl)methylmagnesium bromide readily reacted with various ketones and aldehydes to give the corresponding 2-diazo-(2-trimethylsilyl)ethanols. These were efficiently converted to indazoles bearing hydroxymethyl units at the 3-position by intermolecular [3 + 2] cycloaddition with benzynes.

1- (phthalazin-l'-yl-amino)-3-chloro-4-aryl-4h-(4o-rm ethyl)-2-azetidinones (3) were prepared by cycloaddition of-methyl substituted benzal hydrazinophthalazine (2) with chloro acetylchloride. the hydrazone (2) was synthesised by the condensation of 1- hydrazinophthalazine (1) with substituted aromatic aldehydes, ketones 7 acetophenones. 1- hydrazinophthalazine was prepared from the phthal...