Search results
Results from the WOW.Com Content Network
The reaction typically involves free radical pathways. The regiochemistry of the halogenation of alkanes is largely determined by the relative weakness of the C–H bonds. This trend is reflected by the faster reaction at tertiary and secondary positions. Free radical chlorination is used for the industrial production of some solvents: [2]
More generally, Zaytsev's rule predicts that in an elimination reaction the most substituted product will be the most stable, and therefore the most favored. The rule makes no generalizations about the stereochemistry of the newly formed alkene, but only the regiochemistry of the elimination reaction. While effective at predicting the favored ...
In organic chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. [1] [2] It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will be added.
After addition to a straight-chain alkene such as ethene (C 2 H 4), the resulting alkane will rapidly and freely rotate around its single sigma bond under normal conditions (i.e. room temperature). Thus whether substituents are added to the same side (syn) or opposite sides (anti) of a double can usually be ignored due to free rotation.
Regiochemistry follows from the reaction mechanism, which exhibits halogen attack on the least-hindered unsaturated carbon. The mechanism for this chain reaction resembles free radical halogenation, in which the peroxide promotes formation of the bromine radical. However, this process is restricted to addition of HBr.
Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...
Spoilers ahead! We've warned you. We mean it. Read no further until you really want some clues or you've completely given up and want the answers ASAP. Get ready for all of today's NYT ...
In a free-radical addition, there are two chain propagation steps. In one, the adding radical attaches to a multiply-bonded precursor to give a radical with lesser bond order. In the other, the newly-formed radical product abstracts another substituent from the adding reagent to regenerate the adding radical. [3]: 743–744