Saytzeff, Alexander

If there is possibility of formation of more than one alkene due to the availability of more than one 3-hydrogen atoms, usually one alkene is formed as the major produet. These form part of a pattern first observed by Russian ehemlst, Alexander Zaitsev (also pronounced as Saytzeff) who In 1875 formulated a rule which can be summarised as in dehydrohalogenation reactions, the preferred product is that alkene which has the greater number of alkyl groups attached to the doubly bonded carbon atoms. Thus, 2-bromopentane gives pent-2-ene as the major product. 

The Saytzeff rule (or Zaitsev s rule or Saytsev s rule named after Alexander Mikhailovich Zaitsev) implies that base (sterically unhindered) induced eliminations will lead predominantly to the alkene in which the double bond is more highly substituted. However, if the base, for example, is potassium f-butoxide [(CH3)3COK], the bulkiness prohibits the base from pulling the proton off of the most substituted carbon. In such cases, the less substituted alkene, i.e. Hofmann elimination, is preferred. 

Predominant formation of the more stable isomer is called Saytzeff orientation after the Russian chemist Alexander Saytzeff (University of Kazan), who in 1875 first formulated a rule" for orientation in dchydrohalogenation. 

The Zaitsev elimination, first reported in 1875 by the Russian chemist Alexander Zaitsev (1841-1910), was published in Justus Liebigs Annalen der Chemie and the German spelling of his name, Saytzeff, was used.1 Several historical accounts of Alexander Zaitsev have been reported.2 The olefin forming E2 elimination has been reviewed.3... 

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. 

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]. 

Alexander Saytzeff (University of Kazan) formulated a rule in 1875 concerning elimination based on the observation that in the elimination of hydrogen halides (chlorides and bromides) from alkyl halides, the preferred product is the alkene with the greatest number of alkyl groups attached to the double bond. 

The factors that operate to stabilize alkenes with fiiUy formed double bonds are also operative in the transition states in which there are partially formed double bonds. So, the more alkyl groups, the better, and the El reaction preferentially produces the most substituted alkene possible. This phenomenon is called Saytze Felmiination, after Alexander M. Saytzeff (1841—1910), the Russian chemist who discovered it. ... 

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