Staudinger preparation

In the 1920s, one of the great polymer pioneers, Hermann Staudinger, prepared a formaldehyde polymer of reasonably high molecular weight in the absence of water at low tem-... 

SCHEME 10.11 Asymmetric Staudinger preparation of P-lactams directed by sugar-derived chiral auxiliaries. 

Preparation. Staudinger prepared diphenylketene for the first time by the action of zinc turnings in ether on a-chlorodiphenylacetyl chloride, an intermediate now readily available by the action of phosphorus pentachloride on benzilic acid (1), but evidently the yield was poor. He then tried dehydrohalogenation of... 

The work by Staudinger prepared the ground for physics to intrude into the Pol3uner World — it had become possible to explain physical properties of various pol3uners by taking into account the chain structure of their constituent molecules. But first, polymer scientists had to discern the specific shapes, or conformations, of molecular chains for different pol3rmers. 

It may be concluded that the conversion of functionalized oxiranes into the corresponding aziridines by an azide ring opening followed by a Staudinger ring closure with triphenylphosphine constitutes a general method for the preparation of aziridines with high enantiopurity. 

Staudinger reaction lead to the preparation of unprotected sugar... 

Malonyl dichloride has been prepared from malonic acid and thionyl chloride,4-9 and from carbon suboxide and anhydrous liquid hydrogen chloride.10 This procedure is based on that of Staudinger and Bereza 6 and of Backer and Homan.8... 

Diphenyldiazomethane has been prepared only by oxidation of benzophenone hydrazone.3 The procedure given above is that of Staudinger, Anthes, and Pfenninger, with minor changes. The method of preparation of benzophenone hydrazone given above is a modification of the procedure of Curtius and Rauter-berg.4... 

Ene-nitrile oxidoisoquinolinium betaine 131 was readily prepared from vinyl triflate aldehyde 79 (Scheme 1.14). Palladium-catalyzed cyanation of vinyl triflate 79 with Zn(CN)2 in DMF at 60 °C produced ene-nitrile aldehyde 129 in 85 % yield [54]. Using the previously developed Staudinger-aza-Wittig reduction sequence, aldehyde 129 was coupled with cyclic ketal azide 121 to afford a 79 % yield of amine 130. The cyclic ketal amine 130 was then treated with 9 1 mixture of CH2CI2/TFA to provide ene-nitrile oxidoisoquinolinium betaine 131 in 93 % yield. 

Hermann Staudinger, on developing a new and simple preparation of the monomer, studied the polymerization of isoprene as early as 1910 (42). Stimulated by the differences in physical properties between his synthetic rubber and natural rubber, he turned his full attention to the study of polymers. 

Up until Staudinger entered the field most polymer preparations were isolated events. As examples, in 1872 Baumann described the preparation of an insoluble mass when vinyl chloride was exposed to sunlight (43) just as Simon had formed a jelly of styrene in 1839 (44). Staudinger, however, systematically prepared the materials and studied their preparation as well as properties. By 1920, he was convinced the association theory was incorrect. 

Staudinger and Kupfer2 discovered a very interesting method for the preparation of diazomethane. They observed that when the isonitrile reaction of primary amines was applied to hydrazine, diazomethane,3 and not the expected di-isocyanogen, C=N—N=C, was produced in the manner indicated in the following equations ... 

The aliphatic diazo-compounds can also be prepared by careful dehydrogenation of the hydrazones (with HgO) (Curtius, Staudinger) and, conversely, they are converted into the latter by hydrogenation ... 

Staudinger s method is given as the preparative method in the earlier editions of this work. 

Diphenylketene has been prepared by action of tripropylamine on diphenylacetyl chloride,2 by treating diphenylchloro-acetyl chloride with granulated zinc,3 and by the action of quinoline on diphenylacetyl chloride.4 It is most conveniently prepared by heating phenylbenzoyldiazomethane—a method first described by Schroeter5 and later used by Staudinger.6... 

These building blocks can be obtained either by the Miller cyclization of (5-hydroxy-ct-amino acids or by the Staudinger reaction7 ([2+2] ketene-imine cycloaddition). The procedure reported here follows the second route and has the advantages of being diastereospecific and to proceed in high yield. For a large scale preparation, the harmful and toxic N-methylhydrazine can be replaced by N,N-dlmethyl-1,3-propanediamine. Further transformations of the key intermediate have been reported elsewhere.7 9... 

Diphenylacetyl chloride has been obtained from diphenyl-acetic acid with phosphorus pentachloride, phosphorus oxychloride and phosphorus pentachloride, and thionyl chloride. It has also been prepared by treatment of diphenylketene with hydrogen chloride. The methods of preparation of diphenylketene have been reviewed in an earlier procedure given in this series. To those cited in the earlier procedure should be added the debromination of a-bromodiphenylacetyl bromide with triphenylphosphine. The procedure above is a modification of that described by Staudinger. ... 

Trifluoroalanine has also been prepared by reducing trifluoropyruvate imines (ethyl trifluoropyruvate is available commercially it is prepared either from per-fluoropropene oxide or by trifluoromethylation of ethyl or f-butyl oxalate). These imines are obtained by dehydration of the corresponding aminals or by Staudinger reaction. They can also be obtained by palladium-catalyzed carbonylation of trifluoroacetamidoyl iodide, an easily accessible compound (cf. Chapter 3) (Figure 5.4). Reduction of the imines affords protected trifluoroalanines. When the imine is derived from a-phenyl ethyl amine, an intramolecular hydride transfer affords the regioisomer imine, which can further be hydrolyzed into trifluoroalanine. ... 

Methyl 6-amino-6-deoxy-a-D-glucopyranoside derivatives 2c were synthesized in our laboratory by a somewhat different procedure [31]. 6-0-Sulfonyl or 6-bromo-6-deoxy derivatives of methyl a-o-glucopyranoside were substituted at C-6 by sodium azide. The 6-azido-6-deoxy intermediate was then treated by acyl chlorides in the presence of triphenylphosphine (Staudinger reaction) to afford amido derivatives which were finally de-O-acetylated to give 2c. The same reaction pathway allowed the preparation of 6-alkylamido-6-deoxy-D-glucopy-ranose derivatives, starting from o-glucose [31]. 

Historically, the first reactions involving thiocarbonyl ylides involve the preparation of thiiranes and 1,3-dithiolanes from diazomethane and thiocarbonyl compounds reported early in the last century by Staudinger and co-workers (12,13). Similar reactions have been smdied by Schonberg and co-workers (14—16) during the 1960s, but neither was the reaction mechanism understood nor have thiocarbonyl ylides been recognized as key intermediates. [For some remarks to this subject see (8) and (10) in (17).]... 

Azetidinones on a solid support 49 have been prepared in high yield by Staudinger reaction of a supported imine with an acid chloride in the presence of a base. The liberated p-lactams were of high purity <99TL1249>. Cycloaddition of a ketene intermediate, derived fi"om an azo compound, to an imine having an oxidatively cleavable chiral auxiliary N-substituent was used to obtain p-lactams 50. The trans. cis ratio which varied between 69 31 and 93 7, depended on the nature of the substituents R and R <99S650>. 

Vicinal diazides 85a-c, prepared by the action of sodium azide on the corresponding 3,4-dichloromaleimide, react with triphenylphosphine in refluxing dichloromethane to give 2-amino-l,2,3-triazole derivatives 86a-c (Scheme 9). The stable di-Staudinger side products 87a-c are also produced from the reaction <2005JCX385>. 

Staudinger reaction),615 H2 and a catalyst, Mg or Ca in MeOH,616 N2H4-Pd,617 and tin complexes prepared from SnCl2 or Sn(SR)2.6l i This reaction, combined with RX — RN3 (0-61). is an important way of converting alkyl halides RX to primary amines RNH, in some cases the two procedures have been combined into one laboratory step.61 Sulfonyl azides RS02N, have been reduced to sulfonamides RSO NH2 by irradiation in isopropyl alcohol620 and with NaH.621... 

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