Multicomponent [5 + 2] cycloaddition reaction for the synthesis of 1,4-diazepines: isolation and reactivity of azomethine ylides

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

We provide a comprehensive account of the 1,3-dipolar cycloaddition reactions of azomethine ylides with carbonyl dipolarophiles. Many different azomethine ylides have been studied, including stabilized and non-stabilized ylides. Of the carbonyl dipolarophiles, aldehydes including formaldehyde are the most studied, although there are now examples of cycloadditions with ketones, ketenes and carboxyl systems, in particular isatoic anhydrides and phthalic anhydrides. Intramolecular cycloadditions with esters can also occur under certain circumstances. The oxazolidine cycloadducts undergo a range of reactions triggered by the ring-opening of the oxazolidine ring system.

Straightforward regioselective construction of 3,4-dihydro-2H-1,4-thiazine by rhodium catalysed [3 + 3] cycloaddition of thiirane with 1-sulfonyl-1,2,3-triazole: a pronounced acid additive effect

A rhodium catalyzed regioselective coupling of thiirane with 1-sulfonyl-1,2,3-triazole has been realized to give a formal [3 + 3] cycloaddition product 3,4-dihydro-2H-1,4-thiazine via the 1,3-insertion model of azavinyl carbene.

Base-induced synthesis of N-dialkylaminomethyl-2H-1,2,3-triazoles from N-sulfonyl-1,2,3-triazoles

A facile synthetic method to access N-dialkylaminomethyl-2H-1,2,3-triazoles has been developed from N-sulfonyl-1,2,3-triazoles by a base induced reaction. Moreover, 4-phenyl-1H-1,2,3-triazoles can also give the same product even in the absence of a base at high temperature.

A new method to access triazole-fused spiro-guanidines from the reaction of isothiocyanates tethered N-sulfonyl-1,2,3-triazoles and amines

The reaction of isothiocyanate tethered N-sulfonyl-1,2,3-triazoles and amines afforded asymmetrical guanidines in fair to excellent yields through a two-component tandem reaction process.

New route to 1,4-oxazepane and 1,4-diazepane derivatives: synthesis from N-propargylamines

N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis that are successfully transformed into many significant N-heterocycles.

Facile synthesis of substituted 3-aminofurans through a tandem reaction of N-sulfonyl-1,2,3-triazoles with propargyl alcohols

A relay catalysis strategy for substituted 3-aminofurans synthesis has been developed.

Tandem 1,2-sulfur migration and (aza)-Diels-Alder reaction of β-thio-α-diazoimines: rhodium catalyzed synthesis of (fused)-polyhydropyridines, and cyclohexenes

Rhodium catalyzed synthesis of substituted tetrahydropyridines was accomplished from readily accessible thio-tethered N-sulfonyl-1,2,3-triazoles. The reaction involves tandem rhodium catalyzed 1,2-sulfur migration in β-thio-α-diazoimines, generated from thio-tethered N-sulfonyl-1,2,3-triazoles, to thio-substituted 1-azadiene and subsequent self aza-Diels-Alder reaction. Interestingly, the methodology was effectively extended to the synthesis of fused tetrahydropyridines, dihydropyridines and cyclohexenes through the in situ trapping of the intermediate, 1-azadiene, with various dienophiles such as enol ether, enamine, ketene S,S-acetal, alkyne, alkene and diene. Furthermore, the direct conversion of propargyl sulfides to (fused)-tetrahydropyridines was also achieved through the successful integration of copper and rhodium catalysts in one-pot.

Synthesis of benzofused 1,4-azaborinols via [4 + 2] annulation strategy and its application in indole synthesis

The first general synthesis of benzofused 1,4-azaborinols via [4 + 2] annulation strategy and its application in indole synthesis.

Intramolecular annulation of aromatic rings with N-sulfonyl 1,2,3-triazoles: divergent synthesis of 3-methylene-2,3-dihydrobenzofurans and 3-methylene-2,3-dihydroindoles

The controllable synthesis of 3-methylene-2,3-dihydrobenzofurans 2 and 3-methylene-2,3-dihydroindoles 5 has been developed via cycloisomerization of N/O-tethered aryltriazoles.

A Rh-catalyzed 1,2-sulfur migration/aza-Diels–Alder cascade initiated by aza-vinyl carbenoids from sulfur-tethered N-sulfonyl-1,2,3-triazoles

A novel Rh(ii) catalyzed intramolecular 1,2-sulfur migration/intermolecular aza-Diels–Alder cascade of sulfur-tethered N-sulfonyl-1,2,3-triazoles has been developed, efficiently affording sulfur-containing tetrahydropyridine derivatives.

Divergent synthesis of indole-fused polycycles via Rh(ii)-catalyzed intramolecular [3 + 2] cycloaddition and C–H functionalization of indolyltriazoles

Intramolecular formal [3 + 2] cycloaddition and C–H functionalization of N-sulfonyl triazoles with indoles have been developed to synthesize potential indole-fused polycycles.

Rh(ii)-catalyzed cycloadditions of 1-tosyl 1,2,3-triazoles with 2H-azirines: switchable reactivity of Rh-azavinylcarbene as [2C]- or aza-[3C]-synthon

The Rh(ii)-catalyzed formal [3+2] and [3+3] cycloadditions of 1-tosyl 1,2,3-triazoles with 2H-azirines have been developed, which enable the efficient synthesis of polysubstituted 3-amino-pyrroles and 1,2-dihydropyrazines, respectively.

One-pot synthesis of 2,3-disubstituted dihydrobenzofurans and benzofurans via rhodium-catalyzed intramolecular C–H insertion reaction

Intramolecular sp³ C–H insertion of α-imino carbenoid. One pot synthesis of benzofuran derivatives.

An efficient approach to 1,2,3-trisubstituted indole via rhodium catalyzed carbene Csp3–H bond insertion

A method for convenient synthesis of N-alkyl-2-aryl-indole-3-carbaldehyde via carbene C–H bond insertion.