Saytzeff synthesis

The amino functional group is not commonly encountered in steroid synthesis except perhaps in steroidal alkaloids. However, certain elimination reactions have been shown to have theoretical and limited preparative importance, largely due to the efforts of McKenna and co-workers. The Hofmann rule for 2 elimination predicts that alkaline elimination of quaternary ammonium salts will occur towards the carbon carrying the most hydrogen atoms cf. the converse Saytzeff orientation, above). In cyclohexyl systems, the requirement for diaxial elimination appears to be important, as in other 2 eliminations, and the Hofmann rule frequently is not obeyed [e.g., (116) (117)]. 

On treatment with thionylchloride/2,6-lutidine (37b) is converted into a 80 20-mixture of the Hofmann-olefin (40) and the Saytzeff-olefin (41). By hydrolysis of the mixture, followed by proper workup enantiomerically pure (R)-p-methylene phenylalanine methyl ester 42 can be obtained28. This compound was recently prepared in racemic form in a lengthy synthesis 29). 

Barbier-Wieland degradation Boudroux-Chichibabin synthesis Bouveault aldehyde synthesis Darzens synthesis Friedel-Crafts Reaction Gatterman-Koch reaction Grignard reaction Reformatsky reaction Saytzeff reaction Ullmann coupling reaction Wiirtz coupling reaction Wiirtz-Fittig reaction... 

Saccharic acids. See Aldaric acids Saccharin, 997 Salicylic acid, 737 acetylation of, 952 acidity of, 953 synthesis of, 952-954 Samuelsson, Bengt, 1025 Sandmeyer reactions, 892, 894, 906—907, 919 Sanger, Frederick, 1070—1074, 1101—1102 Sanger s reagent. See l-Fluoro-2,4-dinitrobenzene a-Santonin, 1046 Saponification, 794—799 Sawhorse diagrams, 90—91 Saytzeff. See Zaitsev, Alexander M. Schiemann reaction, 892, 893, 905 Schiff s base, 673, 689. See also Imines Schrbdinger, Erwin, 7 Schrbdinger equation. See Wave equation Scientific method, 217... 

Alexander Mikhaylovich Saytzev (Saytzeff) (Kazan 20 June 1841 (O.S.)-2 September 1910) studied with Kolbe in Marburg and Leipzig, and was professor in the University of Kazan. He discovered the synthesis of primary and secondary alcohols from esters, ketones, and aldehydes by the action of zinc and alkyl iodides (see Reformatsky, p. 858). He also discovered aliphatic sulphoxides. His brother Mikhayl Mikhaylovich (b. Kazan, 30 August 1845), at first his assistant and later manager of a chemical works in Kazan, discovered the reduction of acid chlorides to aldehydes by hydrogen gas in presence of palladium. ... 

This was one of Edward Frankland s last publications in the field of organozinc chemistry from this time on the pace was set by the school of Alexander Saytzeff in Russia. It was from there that the start of the dominating role of zinc in organometallic intermediates for organic synthesis took place. 

The same must have been true of the researchers that continued this type of work at Saytzeff s institute (Sect. 1.2.5). The synthesis of alcohols and of j8-hydroxyacid esters was considerably simplified by avoiding the preliminary preparation of the organozinc compound. 

It was from Saytzeff s laboratory (Sect. 1.2.5) that Reformatsky [4] first reported the successful synthesis of 3-hydroxyalkanoic acid esters with the aid of an intermediate organozinc compound, thus developing the reaction which still bears his name ... 

As mentioned in Sect. 1.2.4, Alexander SaytzeflF and his coworkers, at the end of the nineteenth century, started using allylic halides in the one-batch , one-pot or one-step synthesis of alcohols, a procedure often referred to as the Saytzeff reaction, e.g. by Barbier [3]. 

Saytzeff, Reformatsky and Simmons-Smith Reactions. The metal zinc played an important role in organic synthesis at the end of the nineteenth century, after Frankland [39, 40] had opened up this field of organometallic chemistry and after Saytzeff and coworkers [41, 42] had introduced a considerable number of syntheses with the aid of zinc in that same period (see Sect. 1.2). 

After Barbier [6] introduced magnesium in the Saytzeff reaction , zinc lost its predominant position in this field of synthesis, although it remained the preferred metal in the Reformatsky reaction [43] (see Sect. 1.2.5). 

In 1898, Philippe Barbier (1848-1922) modified SaytzefFs alcohol synthesis by replacing zinc with the more reactive magnesium 7] (Eq. (2.5)). His student Victor Grignard (1871-1935) further developed this substitution [8] and was awarded the Nobel Prize for the same in 1912 ... 

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