Zaitsev, Alexander

Z configuration. 180 assignment of, 180-183 Zaitsev, Alexander M., 384 Zaitsev s rule. 384... 

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... 

Z (stereochemical prefix), 173—175, 199 Z (symbol for atomic number), 7 Zaitsev, Alexander M., 184 Zaitsev s rule, 184, 191, 199, 200 Zidovudine, 1098 Ziegler, Karl, 246, 569 Ziegler-Natta catalyst, 246, 383, 567-570 Zigzag conformations of alkanes, 97 Zinc... 

In 1875 Alexander M Zaitsev of the University of Kazan (Russia) set forth a gen erahzation describing the regioselectivity of p eliminations Zaitsev s rule summarizes the results of numerous experiments m which alkene mixtures were produced by p elim matron In its original form Zaitsev s rule stated that the alkene formed in greatest amount is the one that corresponds to removal of the hydrogen from the f3 carbon hav mg the fewest hydrogens... 

Alexander M. Zaitsev (1841-1910) was born in Kazan, Russia, and received his Ph.D. from the University of Leipzig in 1866. He was professor at the University of Kazan (1870-1903) and at Kiev University, and many of his students went on to assume faculty positions throughout Russia. 

According to Zaitsev s rule, formulated in 1875 by the Russian chemist Alexander Zaitsev, base-induced elimination reactions generally (although not always) give the more stable alkene product—that is, the alkene with more alkyl substituents on the double-bond carbons. In the following two cases, for example, the more highly substituted alkene product predominates. 

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. 

Notice in the equation shown above and in Example 13.7, the major product is the more highly substituted alkene. In 1875 the Russian chemist Alexander Zaitsev developed a rule to describe such reactions. Zaitsev s rule states that in an elimination reaction, the alkene with the greatest number of alkyl groups on the double bonded carbon (the more highly substituted alkene) is the major product of the reaction. 

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... 

Alexander M. Zaitsev, a nineteenth-century Russian chemist, devised a shortcut to predict the more substituted alkene product. He pointed out that the more substituted alkene product is obtained when a proton is removed from the -carbon that is bonded to the fewest hydrogens. This is called Zaitsev s rule. In 2-chloropentane, for example, one j8-carbon is bonded to three hydrogens and the other j8-carbon is bonded... 

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