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Bromocyclopentane is reacted with magnesium turnings in dry tetrahydrofuran making cyclopentyl Grignard reagent, a main precursor in the synthesis of Ketamine. [ 1 ] References
The compound adds trans to alkenes to give 1,2-bis(thiocyanato) compounds; the intermediate thiiranium ion can be trapped with many nucleophiles. [2] Radical polymerization is the most likely side-reaction, and yields improve when cold and dark. [2] [1]: 247 However, the addition reaction is slow, and light may be necessary to accelerate the ...
Alternative Mechanism. The Corey-Winter olefination is a stereospecific reaction: [1] a trans-diol gives a trans-alkene, while a cis-diol gives a cis-alkene as the product. For instance, cis- and trans-1,2-cyclodecanediol gives the respective cis- and trans-cyclodecene.
1,2-Dibromoethylene, also known as 1,2-dibromoethene and acetylene dibromide, is a dihalogenated unsaturated compound with one bromine on each of the two carbon atoms. There are two isomers of this compound, cis and trans. Both isomers are colorless liquids.
Although the mechanisms of each of these reactions differ somewhat, in each case the chiral catalyst or reagent must be involved in the enantio determining conjugate addition step. Cis-epoxides are difficult to access using nucleophilic epoxidation methods. Nearly all nucleophilic epoxidations of cis olefins afford trans epoxides.
Hydroboration of 1,2-disubstituted alkenes, such as a cis or trans olefin, produces generally a mixture of the two organoboranes of comparable amounts, even if the steric properties of the substituents are very different. For such 1,2-disubstituted olefins, regioselectivity can be observed only when one of the two substituents is a phenyl ring.
[1] Diastereoselective epoxidation may be achieved through the use of alkene starting materials with diastereotopic faces. When racemic 3-isopropylcyclohexene was subjected to DMD oxidation, the trans epoxide, which resulted from attack on the less hindered face of the double bond, was the major product. [1]
These have been developed extensively, second only to the classical methylene reagents (R 1 =R 2 =H). The substitution pattern on aryl reagents can heavily influence the selectivity of the reaction as per the criteria above. If the ylide carbon is substituted with an alkyl group the reagent is referred to as an unstabilized ylide. The size of ...