Bond length relationships in diazo and diazonium compounds

Allen, Frank H.; Harris, S.E.

doi:10.1107/s010876819401195x

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…30 The C6-C5 bond length [1.460(3)Å] in 11 is similar to the mean value for conjugated (C )C-C(C O) bonds. 33 Along with these parameters, the bond lengths generally in the C6-C5-C4a-C10a-C6a ring suggest that the canonical form, 11b in Fig. 6, contributes to the overall structure in the solid state.…”

Section: Crystallographymentioning

confidence: 86%

Preparation of α-diazocarbonyl compounds from β-lapachone derivatives and other 1,2-naphthoquinones: use of the 2D NMR1H,15N and1H,13C HMBC techniques in assigning regiochemistry

et al. 2006

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The assignment of the diazo site in products of the reaction of p-toluenesulfonylhydrazine with beta-lapachone, 3,4-dihydro-2,2-dimethyl-2H-naphtho[1,2-b]pyran-5,6-dione, and other 1,2-naphthoquinones in methanol solution at room temperature has been accomplished using 1H,13C HMBC and 1H,15N HMBC NMR experiments. Only one diazo-naphthalenone product was isolated in yields ranging from 50-100% from each reaction. The site of diazo substitution of beta-lapachone and derivatives is the 1-position, in contrast to substitution at the 2-position in 4-MeO-1,2-naphthoquinone. Steric factors, rather than electronic factors, control the reaction site. Along with 2-diazo-1(2H)-naphthalenone, an additional product isolated from the reaction of p-toluenesulfonylhydrazide with 1,2-naphthoquinone was 2-diazo-4-hydroxy-1(2H)-naphthalenone. Confirmation of the formation of 6-diazo-2,2-dimethyl-2,3,4,6-tetrahydro-2H-benzo[h]cromen-5-one, obtained from beta-lapachone, was achieved using single crystal X-ray diffraction.

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Section: Crystallographymentioning

confidence: 86%

Preparation of α-diazocarbonyl compounds from β-lapachone derivatives and other 1,2-naphthoquinones: use of the 2D NMR1H,15N and1H,13C HMBC techniques in assigning regiochemistry

et al. 2006

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“…A search on the Cambridge Crystallography Database (CCD) of all X‐ray solid‐state structures deposited containing a terminal CN 2 group reveals the bond lengths in diazoalkenes to belong to some of the shortest C−N [1.257(7)–1.287(4) Å] and longest N−N [1.147(5)–1.184(7) Å] bond lengths (Figure 4). [49] In fact, there are few compounds being positioned in this unusual area (bottom right corner in Figure 4). Similar bond parameters are obtained by metalated diazo compounds of the structure [M]−C(N 2 )R, for instance [M]=Pd(PPh 3 ) 2 Cl, [50] Rh(PEt 3 ) 3 , [51] or ArSn [52, 53] .…”

Section: Room‐temperature‐stable Diazoalkenesmentioning

confidence: 99%

Diazoalkenes: From an Elusive Intermediate to a Stable Substance Class in Organic Chemistry

Hansmann

2023

Angew Chem Int Ed

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Over decades diazoalkenes (R2C=C=N2) were postulated as reactive intermediates in organic chemistry even though their direct spectroscopic detection proved very challenging. In the 1970/80ies several groups probed their existence mainly indirectly by trapping experiments or directly by matrix‐isolation studies. In 2021, our group and the Severin group reported independently the synthesis and characterization of the first room‐temperature stable diazoalkenes, which initiated a rapidly expanding research field. Up to now four different classes of N‐heterocyclic substituted room‐temperature stable diazoalkenes have been reported. Their properties and unique reactivity, such as N2/CO exchange or utilization as vinylidene precursors in organic and transition metal chemistry are presented. This review summarizes the early discoveries of diazoalkenes from their initial postulation as transient, elusive species up to the recent findings of the room‐temperature stable derivatives.

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“…[32] Eine Suche in der Cambridge Crystallography Database (CCD) nach allen hinterlegten Röntgenfestkörperstrukturen, die eine endständige CN 2 -Gruppe enthalten, zeigt, dass die Bindungsabstände in Diazoalkenen zu den kürzesten CÀ N [1.257(7)-1.287(4) Å] und den längsten NÀ N [1.147(5)-1.184( 7) Å] Bindungsabständen gehören (Abbildung 4). [49] Tatsächlich gibt es nur wenige Verbindungen, die sich in diesem ungewöhnlichen Bereich befinden (rechts unten in Abbildung 4). Ähnliche Bindungsparameter sind in metal-Abbildung 2.…”

Section: Strukturelle Und Spektroskopische Datenunclassified

Diazoalkene – Von einem flüchtigen Intermediat zu einer neuen stabilen Substanzklasse in der Organischen Chemie

Hansmann

2023

Angewandte Chemie

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AbstractÜber Jahrzehnte wurden Diazoalkene (R2C=C=N2) als reaktive Intermediate in der organischen Chemie postuliert, obwohl sich ihr direkter spektroskopischer Nachweis als sehr schwierig erwies. In den 1970/80er Jahren untersuchten mehrere Gruppen ihre Existenz hauptsächlich indirekt durch Abfangexperimente oder direkt durch Matrixisolationsstudien. In 2021 berichteten unsere Gruppe und die Severin Gruppe unabhängig voneinander über die Synthese und Charakterisierung der ersten bei Raumtemperatur stabilen Diazoalkene, was ein schnell expandierendes Forschungsgebiet darstellt. Soweit wurden vier verschiedene Klassen von N‐heterozyklisch substituierten, raumtemperaturstabilen Diazoalkenen beschrieben. Ihre Eigenschaften und einzigartige Reaktivität, wie z. B. N2/CO‐Austausch oder die Verwendung als Vinylidenvorläufer in der organischen und Übergangsmetallchemie, werden vorgestellt. Diese Übersicht fasst die frühen Entdeckungen von Diazoalkenen zusammen, von ihrer anfänglichen Postulierung als flüchtige, schwer fassbare Spezies bis hin zu den jüngsten Erkenntnissen über raumtemperaturstabile Derivate.

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Bond length relationships in diazo and diazonium compounds

Cited by 7 publications

References 4 publications

Preparation of α-diazocarbonyl compounds from β-lapachone derivatives and other 1,2-naphthoquinones: use of the 2D NMR1H,15N and1H,13C HMBC techniques in assigning regiochemistry

Preparation of α-diazocarbonyl compounds from β-lapachone derivatives and other 1,2-naphthoquinones: use of the 2D NMR1H,15N and1H,13C HMBC techniques in assigning regiochemistry

Diazoalkenes: From an Elusive Intermediate to a Stable Substance Class in Organic Chemistry

Diazoalkene – Von einem flüchtigen Intermediat zu einer neuen stabilen Substanzklasse in der Organischen Chemie

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