Azaoxyallyl cations represent a family of versatile and powerful synthetic synthons, which are generally in situ generated from a-halohydroxamates in the presence of organic or inorganic bases. Owing to the unique structural features and reactivities of azaoxyallyl cations, some various efforts have been made to enrich the synthetic methodology of azaoxyallyl cations (Scheme 1, 1). In 2011, Jef...

For the first time [3 + 2] 1,3-cycloaddition of an ionized carbonyl ylide has been observed in gas phase ion-molecule reactions of CH2OCH2 (1) with several carbonyl compounds. The reaction, which competes with electrophilic addition that leads to net CH2 transfer, occurs across the CdO double bond of acetaldehyde and several acyclic ketones yielding ionized 4,4-dialkyl-1,3-dioxolanes as unstabl...

CuO hollow nanostructures have been used for the catalytic [3 + 2] cycloaddition of azides with terminal alkynes to provide the products in good yields with high regioselectivity.

Phosphine-catalyzed [3 + 2] cycloaddition of Morita-Baylis-Hillman carbonates with sulfamate-derived cyclic imines has been developed, affording sulfamate-fused dihydropyrroles in moderate to good yields.

Cyclic ketimines as electrophiles for [2+2] and [3+2] cycloaddition reactions of allenoates have been developed, affording functionalized sultam-fused azetidines and dihydropyrroles, respectively, in good yields with high regioselectivities.

In this work, three possible mechanisms, including mechanisms A and B associated with the stereoselective [2 + 2] cycloaddition product and mechanism C associated with the [2 + 2 + 2] cycloaddition product, have been investigated for N-heterocyclic carbenes (NHCs) catalyzed cycloadditions of ketenes with isothiocyanates by using density functional theory (DFT). Our calculated results suggest th...

The first structurally authenticated [2+2] cycloaddition products of any transition metal hydrazide complexes are reported; cycloaddition products of transition metal hydrazides with alkynes and heteroalkynes have been obtained for the first time; these are the first structurally authenticated cycloaddition products for any transition metal M=NNR(2) functional group.

A resplendent trio: Protic ionic liquids (PILs) with nucleophilic anions served in concert as regenerable reaction medium, Brønsted acid, and a source of nucleophile. Heating donor–acceptor cyclopropanes 1-methylimidazolium thiocyanate (B:⋅HNCS) afforded products formal (3+2)- (4+2)-cycloaddition isothiocyanic acid.

A latent catalyst for the [3+2] cycloaddition reaction of azides and alkynes has been developed in accordance with the principles of Click chemistry.

The copper catalyzed 1,3-dipolar cycloaddition of 4-butoxyphenylazide with 2-, 3- or 4-ethynylpyridine furnishes 1,4-diaryltriazoles, which display turn-on fluorescence upon addition of metal cations.