Synthetic chemistry Williamson synthesis

In addition to its uses in photography and medicine, iodine and its compounds have been much exploited in volumetric analysis (iodometry and iodimetry, p. 864). Organoiodine compounds have also played a notable part in the development of synthetic organic chemistry, being the first compounds used in A. W. von Hofmann s alkylation of amines (1850), A. W. Williamson s synthesis of ethers (1851), A. Wurtz s coupling reactions (1855) and V. Grignard s reagents (1900). 

A few examples will show the importance of these reactions in synthetic organic chemistry. If X is an alkoxide ion, equation (1) describes the Williamson ether synthesis (2). If X is a cyanide ion, (1) describes a standard nitrile preparation (3). If X is an aromatic nucleus, and the departure of the leaving group is facilitated by A1C13, then (1) describes the Friedel-Crafts alkylation (4). With X as the cyanate ion, (1) describes the preparation of isocyanates (5) and if it is ammonia, (1) describes a common method of preparation of amines (6). In addition, nucleophilic transmethylation is a very... 

The synthesis of di- and tetrahydrofurans continues to be one of the most active areas in synthetic organic chemistry. In the construction of tetrahydrofurans, the Williamson cycloetherization has always been a practical approach. Lautens employed a three-step procedure to convert the alcohol shown below to a bis-tetrahydrofuran <02OL1879>. A similar cyclization route was also utilized in the total synthesis of muconin <02TL8661>. 

The concepts surrounding the dendrimer synthesis have been lucidly presented [15, 22], The general synthetic strategy involves the repetitive alternation of a growth reaction and an activation reaction. Often these reactions have to be performed at many sites on the same molecule simultaneously. The growth reaction dictates the way by which the branching is introduced into a dendrimer. Many dendrimer syntheses rely upon traditional reactions, such as the Michael reaction or the Williamson ether synthesis while others involve the use of solid-phase synthesis or organotransition metal chemistry [1, 24]... 

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