Staudinger condensation

Sulfimines 175 are obtained in excellent yield by Staudinger condensation of sulfin-amide 174 with trifluoropyruvates. In contrast, and quite surprisingly, the Staudinger reaction of terf-butylsulfinamide 182 with the pyruvates under the same conditions does not work. Sulfimines 175 are alkylated with Grignard reagents in good yields but with poor to moderate diastereoselectivities (see Scheme 9.39) [67]. 

Carothers had already settled the controversy between Staudinger and his opponents. He had built Staudinger s macromolecules, and the properties of his macromolecules were identical to those of natural polymers. Even more, his path breaking technique of condensation polymerization had demonstrated that his macromolecules consisted of long chains held together by ordinary valence bonds. 

The debate might have ended here had Naturwissenschaften not have published a condensation of Meyer s Zeitschrift fuer Angewandte Chemie paper (28). Staudinger, then wrote in the former publication (32), "An article by K. H. Meyer. .. is a condensation of a previous article. The opinions in these publications about the structure of high molecular weight compounds are presented in a manner I have advocated for years in many publications and speeches. I welcome that the author shares the opinions. . . since no reference was made to my work, I have to assume that K. H. Meyer believes this is common knowledge."... 

Carothers and his research group synthesised many polyesters, nearly all of them aliphatic. His basic patent was filed on July 3, 1931 [23], This work, together with his work on condensation polymers in general, proved influential in convincing the scientific community that polymers were indeed macromolecules, as maintained by Staudinger, and not assemblies of small molecules in a special state of association. Staudinger himself was initially reluctant to accept that the polyesters were polymers, since he had defined polymers in such a way as to refer solely to products of addition reactions. He thus excluded products of condensation reactions, where small molecules were eliminated as co-products of the reaction [24],... 

With the aid of a Knoevenagel condensation and a Staudinger reaction, 2-azidocyclopent-l-ene 1-carbaldehydes (195) can be converted into suitable products for a cyclopenta[b]pyridine synthesis [89JCS(P1)1369], as shown in Scheme 72. In order to bring the ester carbonyl function and the imino-phosphorane group into close proximity suitable for cyclization reactions, the 1,3-diene system 196 should possess the s-cis conformation. Furthermore, the exocyclic double bond should show a cis conformation. To achieve... 

Several condensed systems, especially those combined with pyridine rings, show biological activity, e.g., in the field of crop protection and as anti-virus and anti-cancer compounds. Aza-Wittig reactions in particular should make several novel heterocyclic rings available. The aza-Wittig reaction of iminophosphoranes has to be considered as a major principle in modern synthetic chemistry, as was wisely foreseen by Staudinger and Meyer as early as 1919. 

The Staudinger reaction of imines 481 derived from 7-oxanorbornenone with arylacetic acid chlorides 482 furnished a 0-40 60-100 mixture of C-2-epimeric, spiro-condensed l,3-oxazin+-one derivatives 483 and 484, the ratio of which proved to depend on the substituents on the aromatic rings and on the nitrogen atom (Equation 54) <2002TL6405>. 

Polymer-bound P-lactams have been prepared via the ester enolate imine condensation route <02JOC8034>. On the other hand, an efficient asymmetric synthesis of 2-azetidinones was accomplished when chiral acid chlorides or chiral aldehydes were used in the polymer-supported Staudinger reaction <02TA905>. 

Otto Bayer was aware of the work of Staudinger and Carothers. He was particularly impressed with the latter s discovery of polyamides and its implications for the fiber and textile industries. He knew that in the condensation (linear step-growth) polymerization used to prepare nylon and polyesters a small molecule, usually water, is formed and has to be removed. 

Quinazolines have also been prepared by the reaction of a polystyrene-bound phosphoranimine and isocyanates, followed by an intramolecular cyclization of the carbodiimide intermediate 4-Ferrocenylidene-l-aminoimidazolone derivatives have been obtained from p-ferrocenyl-a-azidoacrylates and isocyanates followed by condensation of the resulting carbodiimidoester with hydrazines " In a Staudinger/ aza-Wittig process and in the presence of PPh3, bimetallic ferrocenyl oxazole derivatives (23) - (26) have been formed by the reaction of a-... 

The majority of reported solid-phase combinatorial syntheses of the lactam core utilize a [2-i-2] cycloaddition reaction of ketenes with resin-bound imines [33-41]. A further development of the Staudinger reaction was reported by Mata and coworkers using Mukaiyama s reagent [42]. In addition, a stereoselective synthesis of chi-rally pure P-lactams has been performed as a first utilization of polymer-supported oxazolidine aldehydes [43]. Other strategies include an ester enolate-imine condensation [44], an Hg(OCOCF3)2-mediated intramolecular cydization [45], and Miller hydroxamate synthesis [46]. Because of the variability derived from the scaffold synthesis, not many attempts have been made to derivatize the resin-bound lactam template [47]. One of the most detailed descriptions of a versatile (3-lactam synthesis on a resin employed amino acids tethered as esters on Sasrin resin [48]. 

Identified by Jaeckle (1898). Its presence was also reported by Reichstein and Staudinger (1926b). Prescott et al. (1937a,b) identified it as its dimethyl dihydroresorcinol condensation product and... 

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