Pivaloylnitrene

Tisue, G. T.; Linke, Siegfried; Lwowski, Walter

doi:10.1021/ja01000a056

Cited by 45 publications

(23 citation statements)

References 1 publication

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“…98 For example, the thermolysis of pivaloyl azide [Bu t C(O)N 3 ] in cyclohexane produces the corresponding isocyanate in 99.4% yield. 100,101 The photolysis of Bu t C(O)N 3 gives isocyanate in a yield of only 40% both in inert solvents and alkenes, which react with acylnitrenes to form the corresponding aziridines. 100,101 The photolysis of benzoyl azide and a series of its derivatives in both inert solvents and solvents giving adducts with acylnitrenes affords isocyanates in similar yields (40% ± 50%).…”

Section: Photochemical Transformations Of Acyl Azidesmentioning

confidence: 99%

Study of photochemical transformations of organic azides by matrix isolation techniques and quantum chemistry

Gritsan¹

2007

Russ. Chem. Rev.

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Section: Photochemical Transformations Of Acyl Azidesmentioning

confidence: 99%

Study of photochemical transformations of organic azides by matrix isolation techniques and quantum chemistry

Gritsan¹

2007

Russ. Chem. Rev.

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“…3-8 Therefore, it was concluded that, even if carbonylnitrenes are formed during photoly sis of carbonyl azides, they do not rearrange to isocyan ates. 2, [4][5][6][7] It was demonstrated 9,10 that direct and triplet sensi tized photolysis of benzoyl azide (1) in alkenes produces the same trapping products and that these products are characteristic of reactions of singlet nitrenes. Similar re sults were obtained for 2 naphthoyl azide and a series of substituted benzoyl azides.…”

mentioning

confidence: 99%

Ground state multiplicity of acylnitrenes: computational and experimental studies

2005

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The singlet-triplet energy splitting (∆E ST = E S -E T ) was calculated for formylnitrene (5) and for the syn and anti rotamers of carboxynitrene HOC(O)N (6) by the CCSD(T) method. Extrapolation of ∆E ST to a complete basis set was calculated to be negative for 5 and strongly positive for 6. Similar results were obtained by the G2 procedure. The reason for the dramatic stabilization of the singlet state appeared to be a special bonding interaction between the nitrogen and oxygen atoms, which results in the structure intermediate between those of nitrene and oxazirene. It was found that the B3LYP/6 31G(d) method overestimates ∆E ST by ~9 kcal mol -1 for 5 and by ~7 kcal mol -1 for 6. Taking into account this overestimation and the results of DFT calculations, it was concluded that benzoylnitrene has a singlet ground state. It was proved experimentally using photolysis of benzoyl azide in an argon matrix at 12 K that benzoylnitrene has a singlet ground state and its structure is similar to that of oxazirene. Nevertheless, these singlet intermediates have low barrier to the aziridine formation, which is traditionally considered to be a typical singlet nitrene reaction.Photolysis of carbonyl azides RC(O)N 3 gives rise to two types of products: (i) isocyanates RNCO (the prod ucts of the photo Curtius rearrangement 1 ) and (ii) bimo lecular trapping products typical of the reactions of sin glet carbonylnitrenes RC(O)N. 2 It has, however, been shown that the yield of isocyanates upon photolysis of a series of carbonyl azides (R = tert butyl, aryl) remains constant (~40 50%) irrespective of the presence or ab

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“…Methyl isocyanate was considered to be a possibility for the species C,H,NO, by rearrangement of an acyl nitrene, but all attempts to isolate or trap the isocyanate were unsuccessful. It is relevant to note that recent investigations of the Curtius and Lossen rearrangements (44,45) in a concerted manner, intramolecular rearrangement of an acyl nitrene being much slower than intermolecular insertion, addition and abstraction reactions.…”

Section: Reactions Of 2-bromo-n-bromoacetimidates Rearrangement To DImentioning

confidence: 99%

On the Reaction of N-Bromoacetamide with Olefins. Preparation and Chemistry of 2-Bromo-N-Bromoacetimidates, a New Class of Compounds

Wolfe¹,

Awang²

1971

Can. J. Chem.

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A historical and mechanistic review of the Wohl-Ziegler reaction (allylic bromination by N-bromoamides and imides) is presented as an introduction to the present work, a re-examination of the reaction of N-bromoacetamide (NBA) with some olefins. The reaction has been found to lead not to allylic bromination but, rather, to 2-bromo-N-bromoacetimidates, a new class of compounds. The stoichiometry of the reaction is: olefin + 2 NBA + adduct + acetamide. The process appears to occur in two stages, viz., a free radical reaction of NBA with itself to form N,N-dibromoacetamide (NDBA), followed by ionic addition of NDBA to the double bond. Hofmann's synthesis of NDBA has been repeated; the compound reacts rapidly with cyclohexene to give the same adduct 10 as does NBA. A variety of stereochemical and selectivity data suggest that this is an ionic addition.The chemical transformations of 2-bromo-N-bromoacetimidates under thermal, acidic, and basic conditions are discussed.Comme introduction au present travail qui est un reexamen de la reaction de la N-bromoacetamide avec quelques olefines, nous presentons une revue historique et mecanistique de la reaction de WohlZiegler (bromuration allylique par des N-bromoamides et imides). On a trouve que la reaction ne conduit pas B la bromination allylique mais plut8t aux bromo-2 N-bromoacCtimidates, une nouvelle classe de composes. La stoichiometrie de la reaction est: olefine + 2 NBA + compose d'addition + acetamide. Le processus semble se produire en deux temps a savoir une reaction radicalique de la NBA sur elle-mCme pour conduire a la N,N-dibromoacktamide (NDBA) suivie d'une addition ionique de la NDBA a I'alcene. La synthese de Hofmann de la NDBA a it6 repitee; ce compose reagit rapidement avec lecyclohCxCne et conduit au produit 10 qui est aussi obtenu sous I'action de la NBA. La steriochimie et la sClectivitC de cette reaction suggerent que I'addition est ionique.On discute aussi des transformations chimiques que subissent les bromo-2 N-bromoacCtamidates sous I'influence de la chaleur, des acides, et des bases.

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Pivaloylnitrene

Cited by 45 publications

References 1 publication

Study of photochemical transformations of organic azides by matrix isolation techniques and quantum chemistry

Study of photochemical transformations of organic azides by matrix isolation techniques and quantum chemistry

Ground state multiplicity of acylnitrenes: computational and experimental studies

On the Reaction of N-Bromoacetamide with Olefins. Preparation and Chemistry of 2-Bromo-N-Bromoacetimidates, a New Class of Compounds

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