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In chemistry a carbenoid is a reactive intermediate that shares reaction characteristics with a carbene. [1] In the Simmons–Smith reaction the carbenoid intermediate is a zinc / iodine complex that takes the form of I-CH 2-Zn-I. This complex reacts with an alkene to form a cyclopropane just as a carbene would do.
The configuration of the product is determined by the trajectory of approach of the olefin to the metal carbene. In reactions of monosubstituted metal carbenes with terminal olefins, the olefin likely approaches "end-on" (with the carbon-carbon double bond of the olefin nearly parallel to the metal-carbon double bond of the carbene) with the olefin R group pointed away from the substituent of ...
The Simmons–Smith reaction is an organic cheletropic reaction involving an organozinc carbenoid that reacts with an alkene (or alkyne) to form a cyclopropane. [1] [2] [3] It is named after Howard Ensign Simmons, Jr. and Ronald D. Smith.
[citation needed] [18] The transition metal carbene complexes can be classified according to their reactivity, with the first two classes being the most clearly defined: Fischer carbenes, in which the carbene is bonded to a metal that bears an electron-withdrawing group (usually a carbonyl). In such cases the carbenoid carbon is mildly ...
In organic chemistry, cyclopropanation refers to any chemical process which generates cyclopropane ((CH 2) 3) rings. It is an important process in modern chemistry as many useful compounds bear this motif; for example pyrethroid insecticides and a number of quinolone antibiotics ( ciprofloxacin , sparfloxacin , etc.).
A transition metal carbene complex is an organometallic compound featuring a divalent carbon ligand, itself also called a carbene. [1] Carbene complexes have been synthesized from most transition metals and f-block metals, [2] using many different synthetic routes such as nucleophilic addition and alpha-hydrogen abstraction. [1]
Depending on the constitution of the carbonyl compound or the acidity of the reaction, a carbon-metal or oxygen-metal bond can form after the compound attaches to the metal surface. [9] Furthermore, Vedeja proposed a mechanism involving the formation of radical anion and zinc carbenoid, followed by reduction to alkane [ 7 ] [ 8 ] (as shown above).
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