Synthesis with Perfect Atom Economy: Generation of Diazo Ketones by 1,3‐Dipolar Cycloaddition of Nitrous Oxide at Cyclic Alkynes under Mild Conditions

Abstract

A cascade of five steps, transforms cyclooctynes in the presence of nucleophiles NuH and nitrous oxide, into the depicted products (see scheme). In another example, nitrous oxide was added at a cycloalkyne at −25 °C to generate the corresponding diazo ketone. In both cases, all three atoms of nitrous oxide were incorporated into the products.

Thiacycloalkynes for Copper‐Free Click Chemistry

“…[15] Its reaction with benzyl azide in CD 3 CN proceeded cleanly with a second-order rate constant of (4.0 AE 0.4) m À1 s À1 , the fastest reported cycloalkyne-azide reaction to date (see Figures S3 and S4 in the Supporting Information). During the preparation of this manuscript, Banert and Plefka reported that TMTH was more reactive than a DIBO-like cyclooctyne in a 1,3-dipolar cycloaddition with nitrous oxide, [16] a result that is consistent with our findings.…”

Synthesis of Azoimidazolium Dyes with Nitrous Oxide

“…[6] A second, and much less explored direction is the utilization of N 2 O as a building block for more complex organic molecules. [7][8][9][10] Organometallic compounds of the alkali [7] and earth alkaline metals [8] are known to react with N 2 O under mild conditions. The products contain nitrogen atoms from N 2 O, but the reactions are often not very attractive from a synthetic point of view (e.g., poor yields are obtained or alternative procedures give better results).…”

SN2P2: A Neutral Five‐Membered Sulfur–Pnictogen(III) Ring

“…Similar to cycloaddition reactions of most 1,3-dipoles, [18] a concerted approach for the dimerization of SNP was found. The transition state (TS1) can be regarded as a weakly bound head-to-tail SNP complex with C 2 symmetry.…”

“…However, the cationic binary sulfurnitrogen 6 p electron ring S 3 N 2 2+ (1,2,4,3,5-trithiadiazole dication) has been structurally characterized. [10] Among these neutral planar 6 p electron ring molecules, only the C 2v -symmetric five-membered OP 4 ring (oxatetraphosphole) was tentatively identified by IR spectroscopy ( 16 O: ñ = 825.7 cm À1 , 18 O: ñ = 790.2 cm À1 ) from the productsgenerated by the photolysis of phosphorus/ozone mixtures in solid Ar or by laser ablation of P 4 O 10 . [11] Computationally, the C 2v -symmetric ring isomer was predicted to be the global minimum on the potential energy surface (PES) of OP 4…”