sir, I had a doubt at 15:29 when the First compound ( Ring Structure containing =O and a double bond ) is Reacted with just RMgX ( ie Strong nu ) then 1,2 addition will take place or 1,4 addition will take place, I am confused as in my notes It is written that Hard nu gives 1,2 addition but the Same compound is given and 1,4 addition takes place ( even though it is given that hard nu gives 1,2 )
Sorry for this exceptionally late reply.. I did see this message. When there is no Copper, there will be a mixture of 1,2-addition and 1,4-addition... Between carbonyl carbon and the beta-carbon, the first one is harder due to higher charge density.. So if your nucleophile is harder (more reactive, like alkyl lithium), it will prefer to add on carbonyl carbon. Reason is reactivity (kinetic factor). Now, if you use softer nucleophile (less reactive, like R2CuLi) addition will take place at beta carbon and reason is thermodynamic. Actually C=C double bond is energetically less stable than C=O bond. Next point: Regarding the hard nucleophile but 1,4-addition. Actually, two factor are there regarding the nucleophilic addition on carbonyl compounds like steric and electronic. In all of previous discussion, we mainly focused on the electronic factor. I mean in which centre charge density is more what is nature of the nucleophile (harder or softer). But if look at the substrate, I mean steric point in the both substrate and nucleophile, that will help you to conclude why harder substance undergoes 1,4- addition.... I suggest you to look at your substrate....
if it is simple carbonyl , then alkyl lithium will prefer to add on C=O (if possible). But increase in bulkiness on carbonyl carbon chances on other side reaction (like alpha-H abstraction or hydride transfer) increase. However, it is always better to comment based on some example.... and for alpha,beta-unsaturated compound first priority is 1,2-addition as alkyl lithium is hard nucleophile... but we should always see real experimental facts before making any comment or generalised statement. Did u get it?
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this concept is directly asked in jee mains 2023 which was unexpected, thank you so much sir for clearing the doubt❤
Thanks for informing this to me....
could you please provide the question which was asked
th-cam.com/video/8GFX5sCvxiE/w-d-xo.htmlsi=5-y0k1dNMmB4hOua@@sambhavkapoor476
@Krenneth thanks buddy
khooob bhaalo
always thankful to indians who make these videos lol, they make it easier to understand any topic
Thanks a lot ...
thank u so much sir it really helped, this question has come in jee mains
Thank you for this information ...
Sir ur doing great work
Thank you ....
Your video is helping a lot... Thank you sir.
Glad to hear that....all the best
sir, I had a doubt at 15:29 when the First compound ( Ring Structure containing =O and a double bond ) is Reacted with just RMgX ( ie Strong nu ) then 1,2 addition will take place or 1,4 addition will take place,
I am confused as in my notes It is written that Hard nu gives 1,2 addition but the Same compound is given and 1,4 addition takes place ( even though it is given that hard nu gives 1,2 )
Sorry for this exceptionally late reply.. I did see this message.
When there is no Copper, there will be a mixture of 1,2-addition and 1,4-addition...
Between carbonyl carbon and the beta-carbon, the first one is harder due to higher charge density.. So if your nucleophile is harder (more reactive, like alkyl lithium), it will prefer to add on carbonyl carbon. Reason is reactivity (kinetic factor). Now, if you use softer nucleophile (less reactive, like R2CuLi) addition will take place at beta carbon and reason is thermodynamic. Actually C=C double bond is energetically less stable than C=O bond.
Next point: Regarding the hard nucleophile but 1,4-addition. Actually, two factor are there regarding the nucleophilic addition on carbonyl compounds like steric and electronic. In all of previous discussion, we mainly focused on the electronic factor. I mean in which centre charge density is more what is nature of the nucleophile (harder or softer). But if look at the substrate, I mean steric point in the both substrate and nucleophile, that will help you to conclude why harder substance undergoes 1,4- addition.... I suggest you to look at your substrate....
thaank you my random indian dude
Welcome
Thank you sir really helpful lecture.
Most welcome...
Sir if we add same steric hinderance at carbonyl carbon then alkyl lithium is added so which product is major
if it is simple carbonyl , then alkyl lithium will prefer to add on C=O (if possible). But increase in bulkiness on carbonyl carbon chances on other side reaction (like alpha-H abstraction or hydride transfer) increase. However, it is always better to comment based on some example.... and for alpha,beta-unsaturated compound first priority is 1,2-addition as alkyl lithium is hard nucleophile... but we should always see real experimental facts before making any comment or generalised statement. Did u get it?
How come the acetal is formed , as the acidic medium is not present , plse explain
Please mention the time in my lecture, from where your doubts are arising.. It s helpful for me to answer.. thanks...
Thank you sir
So nice of you..
Thanku sir...
Welcome ..
सर How you desicide which is harder and which is softer bond
Please mention the time of the video about your confusion