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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% yield. This particular catalyst and set of reaction conditions led to the mostly regioselective and enantioselective 1,6-Michael addition of ethyl sorbate 1 to product 3 .
The designations 1,2 and 1,4 are derived from numbering the atoms of the starting compound where the oxygen is labeled “1” and each atom adjacent to the oxygen are sequentially numbered out to the site of nucleophilic addition. A 1,2-addition occurs with nucleophilic addition to position 2 while a 1,4-addition occurs with nucleophilic ...
In organic chemistry, the oxymercuration reaction is an electrophilic addition reaction that transforms an alkene (R 2 C=CR 2) into a neutral alcohol. In oxymercuration, the alkene reacts with mercuric acetate (AcO−Hg−OAc) in aqueous solution to yield the addition of an acetoxymercury (−HgOAc) group and a hydroxy (−OH) group across the ...
Lithium dimethylcopper (CH 3) 2 CuLi can be prepared by adding copper(I) iodide to methyllithium in tetrahydrofuran at −78 °C. In the reaction depicted below, [ 4 ] the Gilman reagent is a methylating reagent reacting with an alkyne in a conjugate addition , and the ester group forms a cyclic enone .
Note that if a Grignard reagent (such as RMgBr) is used, the reaction with an enone would instead proceed through a 1,2-addition. The 1,4-addition mechanism of cuprates to enones goes through the nucleophilic addition of the Cu(I) species at the beta-carbon of the alkene to form a Cu(III) intermediate, followed by reductive elimination of Cu(I ...
Furthermore, this compound reacts with organocopper compounds from 1,4-addition (Michael addition), or with Grignard reagents 1,2-addition, i.e., with attack of the nucleophile at the carbonyl carbon atom. Cyclohexenone is also used in multi-step synthesis in the construction of polycyclic natural products.
Quinones undergo addition reaction to form 1,4-addition products. [10] An example of 1,4-addition reaction is the addition of hydrogen chloride to form chlorohydroquinone: 1,4-addition reaction of quinone with hydrogen chloride to produce chlorohydroquinone. Quinones can undergo Diels–Alder reactions. [10]
An enone forms an allylic alcohol in a 1,2-addition, and the competing conjugate 1,4-addition is suppressed. The selectivity can be explained in terms of the HSAB theory: carbonyl groups require hard nucleophiles for 1,2-addition. The hardness of the borohydride is increased by replacing hydride groups with alkoxide groups, a reaction catalyzed ...