I. Halogens and NH2 are resonance donorsII. N-acylationI. Blocking Effects of Substituents on BenzeneII. General Rules for Deciding on Directing EffectsI. Blocking Effects of Substituents on Benzenea. If there is an activator on the benzene ring, we know it will direct ortho/para. However, the para position might be blocked. That is how you know ortho position will be the major product by default.b. But if you have two substituents that are both activators (of the same strength, let’s say), then if one position is blocked, the other para position will be the major product because it’s still para to the activator. Remember, para is always more favorable over the ortho position, and many times it goes by what is the best opportunity by default for EAS reaction to carry out.c. Important note: Sulfonation reactions result in a strong deactivator, but the SO3H group is also large and causes steric hindrance. In this instance, if you have an activator (so it directs ortho/para), adding the SO3H group will be favored exclusively in the para position because that SO3H group is so large.II. General Rules for Deciding on Directing Effectsa. Let’s say an activator and a deactivator are both substituents on a given benzene ring and you are trying to do an EAS reaction. What are the directing effects?i. First, you only consider the activator. The deactivator, though directs meta, is outdone by the activator substituent. So you only consider the activating substituents and find the para/ortho position.b. If you have two activators, you have to only look at the strongest activator.i. The stronger activator is going to dominate the directing effects in the EAS reaction, so whatever is ortho/para relative to THE STRONGEST ACTIVATOR is going to be the correct product (para still being major, of course)c. If you have two deactivators, you look at the WEAK deactivator, because the weak deactivator is the closest to an activator, it deactivates the ring the least.i. Therefore the weakest deactivator is going to be directing the electrophile, and the electrophile’s position is relative to the weakest deactivator.ii. RECALL: You cannot do a Friedel Crafts reaction (acylation and alkylation) AT ALL when you have no activators on the ring what so ever.CHEM 0320 1st Edition Lecture 12Outline of Last Lecture I. Halogens and NH2 are resonance donors II. N-acylation Outline of Current Lecture I. Blocking Effects of Substituents on Benzene II. General Rules for Deciding on Directing EffectsCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.I. Blocking Effects of Substituents on Benzene a. If there is an activator on the benzene ring, we know it will direct ortho/para. However, the para position might be blocked. That is how you know ortho position will be the major product by default. b. But if you have two substituents that are both activators (of the same strength, let’s say), then if one position is blocked, the other para position will be the major product because it’s still para to the activator. Remember, para is always more favorable over the ortho position, and many times it goes by what is the best opportunity by default for EAS reaction to carry out.c. Important note: Sulfonation reactions result in a strong deactivator, but the SO3Hgroup is also large and causes steric hindrance. In this instance, if you have an activator (so it directs ortho/para), adding the SO3H group will be favored exclusively in the para position because that SO3H group is so large.II. General Rules for Deciding on Directing Effectsa. Let’s say an activator and a deactivator are both substituents on a given benzene ring and you are trying to do an EAS reaction. What are the directing effects? i. First, you only consider the activator. The deactivator, though directs meta, is outdone by the activator substituent. So you only consider the activating substituents and find the para/ortho position.b. If you have two activators, you have to only look at the strongest activator. i. The stronger activator is going to dominate the directing effects in the EAS reaction, so whatever is ortho/para relative to THE STRONGEST ACTIVATOR is going to be the correct product (para still being major, of course) c. If you have two deactivators, you look at the WEAK deactivator, because the weak deactivator is the closest to an activator, it deactivates the ring the least. i. Therefore the weakest deactivator is going to be directing the electrophile, and the electrophile’s position is relative to the weakest deactivator. ii. RECALL: You cannot do a Friedel Crafts reaction (acylation and alkylation) AT ALL when you have no activators on the ring what so