Staudinger-synthesis

Hodous BL, Fu GC (2002) Enantioselective Staudinger synthesis of P-lactams catalyzed by a planar-chiral nucleophile. J Am Chem Soc 124 1578-1579... 

A study of the Staudinger synthesis of /3-lactams from a diazo ketone, an acid chloride, and an imine (under basic conditions) has explored the cis/trans selectivity as a function of time, temperature, solvent, and the order of addition of reagents.81... 

The Staudinger synthesis of a PI phosphazene is a simple modification of the above protocol, where triphenylphosphine is substituted with a triaminophosphine—a... 

The Staudinger synthesis is catalysed by NHCs (A -heterocyclic carbenes), via Ye s possible ketene-first or imine-first mechanisms. To test these alternatives, four zwitterionic NHC adducts have been prepared two using A -tosyl benzaldimine and two using diphenylketene. All four adducts had 1 1 stoichiometry and have been extensively characterized by H- and C-NMR, X-ray crystallography and catalytic tests. The imine-derived zwitterions proved poor catalysts, whereas those derived from diphenylketene replicated the free carbene catalysts, strongly supporting the ketene-first route. 

The first synthetic route for isocyanates was reported in 1848 (10,11)- Subsequent efforts by Hofmann, Curtius, and Hentschel pioneered alternative synthetic approaches (12). These efforts highlighted the phosgene—amine approach. Staudinger presented the stmctural similarities between isocyanates and ketenes and stimulated interest in this class of compounds (13). However, it was not until 1945, when the world was pressed for an alternative to natural mbber, that synthetic routes to isocyanates became an area of great importance. Several excellent review articles covering the synthesis and chemistry of isocyanates have been presented (1 9). 

Asymmetric synthesis of 3-amino (3-lactams via Staudinger ketene-imine cycloaddition reaction 98KGS1448. 

A similar microwave-assisted cyclization in the presence of ammonium acetate of an a-ketoamide, obtained by acylation of an a-aminoketone, was recently described for the synthesis of the antifungal agent Nortopsedin D [46]. The problem of the instabiUty of the a-amino ketones was successfully resolved by in situ acylation of the amine derived from Staudinger reaction of the azide 50 with a phosphine (Scheme 16). This ketoamide was... 

Zhang YR, He L, Wu X, Shao PL, Ye S (2008) Chiral N-heterocyclic carbene catalyzed Staudinger reaction of ketenes with imines highly enantioselective synthesis of W-Boc P-lactams. Org Lett 10 277-280... 

Scheme 7.6. Synthesis of (-)-vasicinone (7-15) by a domino Staudinger-reduction/aza-Wittig reaction.

The Staudinger/aza-Withg procedure has recently also been used by Mellet and Fernandez for the synthesis of calystegine B2, B3, and B4 analogues, emphasizing the growing importance of this methodology [12]. 

Kosiova I, Janicova A, Kois P (2006) Synthesis of coumarin or ferrocene labeled nucleosides via staudinger ligation. Beilstein J Org Chem 2 2-23... 

An elegant synthesis of the spiroaminal containing domain of azaspiracids 201 makes use of a Staudinger-aza-Wittig reaction in a cascade sequence to generate the spiroaminal 202 <06T5338 06JA15114>. 

Figure 17.12 Azido derivatives of sugars can be used as monomers for glycan and carbohydrate synthesis by cells. Such modifications can be probed using click chemistry or Staudinger ligation reactions.

Xu, J., DeGraw, A.J., Duckworth, B.P., Lenevich, S., Tann, C.-M., Henson, E.C., Gruber, S.J., Barany, G., and Distefano, M.D. (2006) Synthesis and reactivity of 6,7-dihydrogeranylazides reagents for primary azide incorporation into peptides and subsequent Staudinger ligation. Chem. Biol. Drug Des. 68, 85-96. 

In the early days of polymer science, when polystyrene became a commercial product, insolubility was sometimes observed which was not expected from the functionality of this monomer. Staudinger and Heuer [2] could show that this insolubility was due to small amounts of tetrafunctional divinylbenzene present in styrene as an impurity from its synthesis. As little as 0.02 mass % is sufficient to make polystyrene of a molecular mass of 2001000 insoluble [3]. This knowledge and the limitations of the technical processing of insoluble and non-fusible polymers as compared with linear or branched polymers explains why, over many years, research on the polymerization of crosslinking monomers alone or the copolymerization of bifunctional monomers with large fractions of crosslinking monomers was scarcely studied. 

Scheme 6 The first synthesis of norchysanthemic acid by Staudinger and re-examination by Crombie...

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