Synthesis and use of a cost-effective,aqueous soluble diazo transfer reagent – m-carboxybenzenesulfonyl azide

Herein, we report the preparation and use of m-carboxybenzenesulfonyl azide as a diazo transfer reagent. This compound is an inexpensive and potentially scalable alternative to many of the diazo transfer reagents currently available, most of which have hazards associated with their use. Its usefulness and suitability as a diazo transfer reagent was assessed on the basis of cost, safety and its effectiveness in diazo transfer to a variety of different substrates.     

Octakis(3‐azidopropyl)octasilsesquioxane: A Versatile Nanobuilding Block for the Efficient Preparation of Highly Functionalized Cube‐Octameric Polyhedral Oligosilsesquioxane Frameworks Through Click Assembly

A one‐step synthesis of octakis(3‐azidopropyl)octasilsesquioxane from commercially available octakis(3‐aminopropyl)octasilsesquioxane has been developed through a highly efficient diazo‐transfer reaction under very mild conditions. Nonaflyl azide is shown to be a safer, cheaper, and more efficient reagent for this transformation than the better known and generally used diazo‐transfer reagent triflyl azide. Octakis(3‐azidopropyl)octasilsesquioxane is an excellent nanobuilding block that can be readily octafunctionalized with a range of terminal alkynes by copper(I)‐catalyzed 1,3‐dipolar azide–alkyne cycloaddition to provide new functional nanocages, maintaining a perfect 3D cubic symmetry. The mildness, simplicity, and efficiency of this approach have been demonstrated in the preparation of a glyco‐polyhedral oligosilsesquioxane (POSS) conjugate and a BODIPY–POSS cluster (BODIPY=boron dipyrromethene).     

Efficient synthesis of sulfonyl azides from sulfonamides

Triflyl azide serves as an efficient diazo transfer reagent in this first direct synthesis of sulfonyl azides from readily available and stable sulfonamides. The process is experimentally simple, mild, and high-yielding. Sulfonyl azides participate in various catalytic transformations providing rapid access to diversely functionalized sulfonamide derivatives in good yields.     

Synthesis of α‐Nitro‐α‐diazocarbonyl Derivatives and Their Applications in the Cyclopropanation of Alkenes and in O?H Insertion Reactions

A facile and highly efficient method for the preparation of α‐nitro‐α‐diazocarbonyl derivatives by a diazo‐transfer reaction involving (trifluoromethyl)sulfonyl azide has been developed. These substrates undergo a rhodium‐catalyzed cyclopropanation reaction with a variety of alkenes. A systematic study of the reaction indicated that the diastereoselectivity of the cyclopropanation could be effectively controlled through the modification of the steric bulk of the diazo reagent. A novel O? H insertion reaction of the metal? carbene complex derived from the α‐nitro‐α‐diazocarbonyl reagent afforded the corresponding novel α‐nitro‐α‐alkoxy carbonyl derivatives.     

Azidation of β-carbonyl lactones and lactams

The direct azidation of various heterocyclic β-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as l-proline or TBD, the direct α-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of α-halogenation and subsequent displacement with azide ion.     

Novel method for synthesis of aryl hydrazones from α-diazo esters: scope and limitations of nucleophiles

Aryl hydrazones, the precursor of Fischer indole synthesis, were easily obtained by nucleophilic addition of aryllithium reagents to diazo esters. The aryl hydrazones were converted into indoles in good yields by heating with thionyl chloride in alcohol. Grignard reagent was also a good nucleophile, whereas organozinc reagent did not react with diazo esters. Aryllithium reagents were prepared by reacting aryl bromides having various substitutions at 2-, 3-, 4-, or multi positions with n-BuLi. The addition of nucleophiles derived from bromopyridines to diazo esters also gave hydrazones.     

New Methods of Preparative Organic Chemistry. Transfer of Diazo Groups

When an arenesulfonyl azide, particularly p-toluenesulfonyl azide, reacts, in the presence of a base, with a compound containing an active methylene group, the two hydrogen atoms of the active methylene group are replaced by a diazo group to form a diazo compound and an arenesulfonamide. The method may be used for the synthesis of the diazo derivatives of cyclopentadienes, cyclohexadienes, 1,3-dicarbonyl, 1,3-disulfonyl, and 1,3-ketosulfonyl compounds, ketones, carbonic acid esters, and β-iminoketones. Secondary reactions can lead to azo compounds and heterocycles such as 1,2,3-triazoles, 1,2,3-thiadiazoles, and pyrazolin-4-ones. Azidinium salts react in the same way, but in this case an acidic reaction medium is necessary, a fact that is sometimes advantageous.     

Inside Cover: A Phosphine‐Mediated Conversion of Azides into Diazo Compounds (Angew. Chem. Int. Ed. 13/2009)

In 1919 H. Staudinger and J. Meyer reported the reductive fragmentation of an azide to an amine. In their Communication on page 2359 ff., E. L. Myers and R. T. Raines report the complementary reaction—cleavage of the other N? N bond in an azide to yield a diazo compound. Both transformations rely on a reagent that contains P^III. The painting, The Alchymist, in Search of the Philosopher's Stone, Discovers Phosphorus, by J. Wright (1771), depicts the discovery of phosphorus by H. Brandt in 1669 (cover art by H. A. Steinberg).

     

Synthesis of Functionalized Cyclopentene Derivatives from Vinyldiazo Compounds and Vinylazides through Sequential Copper‐Promoted [3+2] Cycloaddition/Azide Rearrangement

The reaction of vinylazides with alkenyldiazo compounds in the presence of [Cu(CH₃CN)₄][BF₄] provided cyclopentene derivatives with retention of the azide functionality. This process likely involves a sequence comprising: 1) decomposition of the diazo component with generation of a copper alkenylcarbene species; 2) stepwise regioselective [3+2] cycloaddition; 3) allylic azide rearrangement. This method is compatible with a broad range of substrates. We also show that the azide‐containing cycloadducts can be efficiently converted into the corresponding amine and triazole derivatives.     

Trifluoromethanesulfonyl azide: an efficient reagent for the preparation of α-cyano-α-diazo carbonyls and an α-sulfonyl-α-diazo carbonyl

The reaction scope of trifluoromethanesulfonyl azide in diazo transfer reactions was extended to include the preparation of α-cyano-α-diazo-carbonyls, phenyl sulfonyl diazoacetophenone and diethyl diazomalonate in high yields. The effect of the bases used in the diazo transfer reactions were found to have a dramatic influence on the success of the reaction with pyridine being the base of choice.     

High-load, soluble oligomeric benzenesulfonyl azide: application to facile diazo-transfer reactions

The development of a high-load, soluble oligomeric sulfonyl azide using ROM polymerization is reported. The utility in diazo transfer reactions with active methylene compounds is demonstrated using an efficient protocol, with most reactions showing completion in 30 min. The sulfonamide byproduct, being insoluble in the reaction solvent, can be completely removed by simple filtration through a silica gel SPE cartridge.     

Wavelength-dependent photochemistry of Diazo Meldrum's acid and its spirocyclic isomer,Diazirino Meldrum's acid: Wolff rearrangement versus isomerization

Photoreaction of diazo Meldrum's acid (1) shows a unique wavelength selectivity. At 254 nm it results in efficient (phi(254) = 0.34) Wolff rearrangement, while irradiation with 355 nm light leads to a completely different process, isomerization into corresponding cyclic alpha,alpha"-dicarbonyl diazirine 2 (phi(350) = 0.024). UV photolysis of diazirine 2 is accompanied by two competing processes: loss of nitrogen followed by the Wolff rearrangement and isomerization into diazo compound 1. Thermal decomposition of 1 leads to clean Wolff rearrangement, while heating of 2 causes quantitative conversion into diazo isomer 1.     

A safe and convenient method for the preparation of triflyl azide, and its use in diazo transfer reactions to primary amines

A safe and convenient method for the copper(II)-catalyzed diazo transfer from triflyl azide to primary amines is reported. By replacing CH₂Cl₂ by toluene the formation of hazardous side products, for example, azido-chloromethane and diazidomethane can be avoided.     

Synthesis of new [1,2,3]triazoles and 1H-tetrazoles via reactions of 3,(5)-(Di)chloro-2H-1,4-(benz)oxazin-2-ones with diazocompounds or sodium azide

Treatment of 3,(5)-(di)chloro-2H-1,4-(benz)oxazin-2-ones with diazo compounds or sodium azide yields bi(tri)cyclic compounds which can be converted into [1,2,3]triazoles or 1,5-disubstituted tetrazoles via reactions with nucleophiles as methanol, water and amines.     

Visible-light-mediated tungsten-catalyzed C-H amination of unactivated alkanes with nitroarenes

Science China Chemistry - Alkylamines are important motifs in pharmaceutical and material sciences. The existing reports of C-H amination are limited to ammonia, diazo and azide nitrogen sources....     

Multicomponent Reactions Involving Diazo Reagents: A 5-Year Update

This review summarizes recent developments in multicomponent reactions of diazo compounds. The role of diazo reagent and the type of interaction between components was analyzed to structure the discussion. In contrast to previous reviews on related topics mostly focused on metal catalyzed transformations, a substantial amount of organocatalytic or catalyst-free methodologies is covered in this work.     

Preparation of Novel 1,2,3-Triazoles and a Comparative Study Involving Two Recent Methods for 1,2,3-Triazole Synthesis

Abstract

The syntheses of three novel 1,2,3-triazoles and a comparative study involving two recent methods of 1,2,3-triazole synthesis by diazo group transfers to enaminones, 5,7-dinitro-3-diazo-isatine and mesyl azide, are described. It was observed that the former is the more general and promising method for the synthesis of any 1,2,3-triazole but, when both methods work the mesyl azide one generally gives better yields.     

Simple and efficient solid-phase preparation of azido-peptides

A shelf-stable and easily prepared diazotransfer reagent, imidazole-1-sulfonyl azide hydrochloride, was used to transform the N-terminus of a model peptide on solid phase into an azide moiety. It is demonstrated that this conversion was accomplished within 30 min with high efficiency under aqueous conditions on a NovaPEG resin or in DMF on polystyrene beads.     

Multielectron reduction of diazoalkane and azides via reversible cyclometalation in ditantalum complexes

Reactions of the cyclometalated hydride complexes with diazo and azide substrates are reported. While diazoalkane undergoes four-electron N-N bond cleavage, azides undergo two-electron N(2) extrusion.     

Alkyl Halide‐Free Heteroatom Alkylation and Epoxidation Facilitated by a Recyclable Polymer‐Supported Oxidant for the In‐Flow Preparation of Diazo Compounds

Highly reactive metal carbenes, generated from simple ketones via diazo compounds, including diazo‐amides and ‐phosphonates, using a recyclable reagent in‐flow, are transient but versatile electrophiles for heteroatom alkylation reactions and for epoxide formation. The method produces no organic waste, with the only by‐products being water, KI and nitrogen, without the attendant hazards of isolation of intermediate diazo compounds.