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For example, the image below shows the addition of ethylmagnesium bromide to ethyl sorbate 1 using a copper catalyst with a reversed josiphos (R,S)-(–)-3 ligand. [35] This reaction produced the 1,6-addition product 2 in 0% yield, the 1,6-addition product 3 in approximately 99% yield, and the 1,4-addition product 4 in less than 2%
In organic chemistry, syn-and anti-addition are different ways in which substituent molecules can be added to an alkene (R 2 C=CR 2) or alkyne (RC≡CR).The concepts of syn and anti addition are used to characterize the different reactions of organic chemistry by reflecting the stereochemistry of the products in a reaction.
The Mukaiyama aldol addition is a Lewis acid-mediated addition of enol silanes to carbonyl (C=O) compounds. In this reaction, compounds with various organic groups can be used (see educts). [3] A basic version (R 2 = H) without the presence of chiral catalysts is shown below. Simplified overview with a stereocenter
The aldol reaction (aldol addition) is a reaction in organic chemistry that combines two carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might involve the nucleophilic addition of an enolized ketone to another:
An addition reaction is the reverse of an elimination reaction, in which one molecule divides into two or more molecules. For instance, the hydration of an alkene to an alcohol is reversed by dehydration. There are two main types of polar addition reactions: electrophilic addition and nucleophilic addition.
With 1-methyl-4-t-butylcyclohexene, oxymercuration yields only one product – still anti addition across the double bond – where water only attacks the more substituted carbon. The reason for anti addition across the double bond is to maximize orbital overlap of the lone pair of water and the empty orbital of the mercuronium ion on the ...
Some adjustments may be required to preserve the correct pairing. If stereochemistry is specified, adjustments must be made; see § Stereochemistry below. The one form of branch which does not require parentheses are ring-closing bonds: the SMILES fragment C1N is equivalent to C(1)N , both denoting a bond between the C and the N .
This type of reaction is also called a 1,2-nucleophilic addition. The stereochemistry of this type of nucleophilic attack is not an issue, when both alkyl substituents are dissimilar and there are not any other controlling issues such as chelation with a Lewis acid, the reaction product is a racemate. Addition reactions of this type are numerous.