Ortho para directing groups are electron-donating groups. Ortho para and meta substitution in toluene.
Since NO 2 is an electron withdrawing group a glance at the resonance structures shows that the positive charge becomes concentrated at the ortho-para positions.
Ortho meta para directing groups table. In terms of regioselectivity some groups promote substitution at the ortho or para positions whereas other groups favor substitution at the meta position. Ortho para and meta substitution in toluene. Similarly determine whether -CH 3 is ortho-para directing or meta-directing.
Activating groups serve as orthopara directors when they are. One group reacts to make mixtures of ortho and para productsThere may be different ratios of ortho to para and there may be small amounts of meta- but dont get bogged down in. There are three relative positions for a disubstituted benzene ring.
In looking at the table you might see that there are two groups of substituents. Ortho para directing groups are electron-donating groups. An atom or group already attached to a benzene ring may direct an incoming electrophile to either the orthopara positions or the meta position.
What r meta directing para directing groups giv examples. Atoms or groups that make the benzene molecule more reactive by increasing the rings electron density are called activating groups. The halide ions which are electron-withdrawing but ortho para directing are the exception.
The first exercise is to make sure you know which groups are activators and deactivators as well as how that relates to the Ortho- Para- and Meta directing effects. Meta-Directing Groups The meta-directing groups in Table 162 are all polar groups that do not have an unshared electron pair on. Ortho-para directors I.
Meta directing groups are electron-withdrawing groups. All meta directing groups All other things being equal a third group is less likely to enter between two groups for steric reasons When a meta directing group is meta to an op directing group the incoming electrophile goes predominantly ortho to the meta directing group rather than para to it there is currently no good explanation. Thus the nitro group is a meta directing group.
Hi EveryoneThis is another requested videoI have tried to make it easy and convenient for youIf you liked my effort and video do not forget to subscribe m. All the functional groups are divided into ortho - para or meta -directors. Deactivators halogens are ortho-para directing.
Meta directing groups are electron-withdrawing groups. The second practice problem is built on this and gives specific examples where you need to predict the major product of each Electrophilic Aromatic Substitution reaction. Thus these positions are deactivated towards electrophilic aromatic substitution.
The presence of ortho and para directing group gives a stable cation only when the substituents enter the ortho and para position with respect to the substituent already present. This the meta product and the meta product is not observed in high yields for this reaction so we say that the methoxy group is an orthopara director and we could also label this as being the ortho position on this side and we can say this is the meta position because of symmetry but the meta. Inductive effects of alkyl groups activate the direction of the ortho or para substitution which is when s electrons gets pushed toward the ring.
To which one the group belongs depends on how it stabilizes or destabilizes the transition state of the electrophilic substitution reaction. Thus the nitro group is a meta directing group. Hence NO 2 is a meta-director as we all learned in organic chemistry.
These groups are called either orthopara directing or meta directing respectively. Ortho meta and para. Sometimes the proportion of ortho and para is very high and meta compound formation is very low.
Quick way is to know the logic behind a group being Ortho-Para activating Ortho-Para deactivating or Meta Deactivating. This video is on The role of Ortho Meta Para directing groups in Aromatic Electrophilic Substitution Reaction which will be useful to basic chemistry learn. Deactivators not halogens are meta-directing.
Because reaction at the ortho or para position gives the more stable carbocation alkyl groups are ortho para-directing groups. The presence of the ortho and para directing group gives a stable cation only when the substituents enter the ortho and para position with respect to the substituent already present. While the other groups that increase substitution at the meta position are called meta directing groups.
Thus the methyl group is an ortho para directing group. The left column contains o-p groups and right column co. In addition some groups will increase the rate of reaction activating while others will decrease.
Jan 26 2021 Common ortho para directing groups. Deactivating group meta directors The deactivating groups deactivate the ring by the inductive effect in the presence of an electronegative atom that withdraws electron density away from the ring. Therefore depending on the character of the initial substituent R a subsequent substituent would be placed at the ortho or para position if R is an activatorhalogen or at the meta position if it is a deactivator but not a halogen.
8242020 Thus the methyl group is an ortho para directing group. The halide ions which are electron-withdrawing but ortho para directing are the exception. Sometimes the proportion of ortho and para is very high and meta compound formation is very low.
I have attached a table I made explaining which group is what and why.
