Metathesis

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metathesis

[mə′tath·ə·səs]
(chemistry)
A reaction involving the exchange of elements or groups as in the general equation AX + BY → AY + BX.

Metathesis

 

one of the types of combinative sound changes, consisting of the transposition of sounds or syllables within a word.

Metathesis is found:

  1. In historical phonetic changes; for example, Russian lo- replaced Common Slavic ol- at the beginning of a word, as in Old Russian lodiia, “boat.”
  2. In the borrowing of words from other languages; for example, Ket garnitsa from Russian granitsa, “border.”
  3. In morphophonological alternations; for example, Georgian Su&qmetl, “fifteen” (not SquSmetl ), from qu&l, “five.”

Metathesis is especially common in substandard (colloquial or dialectal) speech; for example, Russian substandard perelinka for the standard pelerinka, “pelerine,” “cape,” by analogy with the prefix pere-. Metathesis may take place when sounds occur in close proximity (for example, Russian mramor from Latin marmor, “marble”) or when they occur at a distance (for example, Russian futliar from German Futteral, “case”). A special kind of metathesis is quantitative metathesis, whereby the quantitative characteristics (length) of sounds are exchanged, while their qualitative characteristics are retained (as in the Greek transformation of teos to teos).

Metathesis is used in literature for humorous effects (for example, S. Marshak’s poem “How Absentminded He Is”).

V. M. ZHIVOV

References in periodicals archive ?
Some procedures illustrate the value of alkyne chemistry and the emerging importance of alkyl metathesis reactions. Asymmetric transformations, especially catalytic processes, are represented by several preparations of chiral catalyst precursors.
Metathesis reactions streamline and simplify the synthesis route while incurring fewer byproducts, thus resulting in more environmentally friendly production.
By targeting the carbon-carbon double bond, which is usually difficult to break, metathesis reactions provide "a new way to link molecules together," says Ronald Breslow, a chemist at Columbia University and Grubbs' Ph.D.
Metathesis reactions are predominantly thermodynamically driven and mechanistically represent a series of carbene exchange reactions.
Chapter topics include alkylation and allylation adjacent to a carbonyl group, asymmetric alkylation or aminatin of allylic esters, Suzuki, Beck and Sonogashira coupling reactions, cross-coupling reactions, regioselective or asymmetric 1,2-addition to aldehydes, olefin metathesis reactions, cyclization reactions, asymmetric aldol and Michael reactions, and steroeselective hydroformylation, carbonylation and carboxylation reactions.