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The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol . This reaction was developed by Alexander Williamson in 1850. [ 2 ] Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an S N 2 reaction .
18-Crown-6 can be synthesized by the Williamson ether synthesis using potassium ion as the template cation. Structure of nickel-aquo nitrate complex of the ligand derived from the templated trimerization of 2-aminobenzaldehyde. [5] The phosphorus analogue of an aza crown can be prepared by a template reaction. [6]
The leaving group X in the organic partner is usually a halide, although triflate, tosylate, pivalate esters, and other pseudohalides have been used. [15] Chloride is an ideal group due to the low cost of organochlorine compounds.
Alexander Williamson. Williamson is credited for his research on the formation of unsymmetrical ethers by the interaction of an alkoxide with a haloalkane, known as the Williamson ether synthesis. He regarded ethers and alcohols as substances analogous to and built up on the same type as water, and he further introduced the water-type as a ...
In accordance with an E2 elimination the reaction with t-butyl chloride results in a KIE of 2.3. The methyl chloride reaction (only S N 2 possible) on the other hand has a KIE of 0.85 consistent with a S N 2 reaction because in this reaction type the C-H bonds tighten in the transition state. The KIE's for the ethyl (0.99) and isopropyl (1.72 ...
For example, the synthesis of macrocidin A, a fungal metabolite, involves an intramolecular ring closing step via an S N 2 reaction with a phenoxide group as the nucleophile and a halide as the leaving group, forming an ether. [2] Reactions such as this, with an alkoxide as the nucleophile, are known as the Williamson ether synthesis.
As a consequence, alkoxides (and hydroxide) are powerful bases and nucleophiles (e.g., for the Williamson ether synthesis) in this solvent. In particular, RO − or HO − in DMSO can be used to generate significant equilibrium concentrations of acetylide ions through the deprotonation of alkynes (see Favorskii reaction). [36] [37]
15-Crown-5 is a crown ether with the formula (C 2 H 4 O) 5. It is a cyclic pentamer of ethylene oxide that forms complex with various cations , including sodium (Na + ) [ 2 ] and potassium (K + ); [ 3 ] however, it is complementary to Na + and thus has a higher selectivity for Na + ions.