in this video we're going to go over grite reactions so we have methyl bromide and we're going to add magnesium to it so what's going to happen this is going to create the grite reagent and the Magnesium atom is going to insert itself between the carbon and the bromine atom so that's methyl magnesium bromide uh whenever you want to carry out an a grin reaction you need to use an ether solvent you can't use a produ solvent like water or like an alcohol because the griny reagent will immediately grab a hydrogen from water or alcohol and deactivate itself so you need to use an ether solvent but now let's talk about how this reaction Works magnesium is in the second column of the periodic table and so it has two valence electrons and magnesium is a very reactive metal it wants to get rid of those two electrons kind of like a Hy potato so it shoots off those two electrons and carbon accepts it and at the same time this Bond breaks because bromine is more electronegative than carbon bromine is going to pull those electrons toward itself so what we now have is a carbon atom that has well a carbon ion I should say that has three hydrogen atoms and a lone here so the carbon has a negative charge magnesium lost two electrons so now it has has a plus two charge and bromine it took those electrons in that Bond so now it has eight lone pairs I mean eight dots or four lone Pairs and bromine now has a minus one charge so our carbon with negative charge is not very stable so carbon immediately bonds with this positively charged magnesium ion this is the way I like to see it by the way so now carbon is attached to it and so magnesium had a plus two charge carbon had a minus one charge if we add those numbers together now magnesium has a net plus one charge which it combined with the bromide ion and so now we have ethyl magnesium bromide that's a nice and simple way to see like how the green is form when you add magnesium to an alkoh haly but now let's talk about what happens if we add the grin reagent to water if we add it to H2O the grite reagent will grab a hydrogen expel hydroxide and you're going to get methane you're also going to have magnesium plus two a bromide ion and hydroxide ion in a solution now keep in mind here what we really have is a carbon with a negative charge this is really the net ionic reaction this carbon grabs the hydrogen and expels hydroxide so that's why we get CH4 and hydroxide the mg plus2 and the bromide ion they're basically Spector ions in this reaction so they're just there for the ride this is called Phenom magnesium bromide and and if we react it with water the carbon is going to grab a hydrogen and turn into Benzene so basically all you have to do is replace the mgbr group with a hydrogen if we add um d2o which is basically water but the only difference is instead of the hydrogen atom we have um the uh duum isotope so this Gren will grab a tutum atom and expel the OD group so instead of adding hydrogen we now have the isotope of hydrogen which is dyum now let's talk about the ulation of gr agents so here we have um buto magnesium bromide and we can react it with another aloh haly so this carbon will attack this carbon that has the bromine atom and this Bond will break and we simply can connect them together so now we have a total of nine carbon atoms this is direct ulation so let's say if we have this Gren reagent and we choose to add this particular Aqua haly what do you think the product for this reaction will be well we know that the grenade is going to attack this carbon and expel the leading group now if you want to draw it start with what you see on the left side which is basically this five carbon ring and it's going to attach to this carbon so let's count it 1 2 2 3 four five so we're going to add five carbons in a straight chain 1 2 3 four five we don't have anything special in carbon one on Carbon 2 we have a methyl group nothing on carbon 3 and on carbon 4 we have two methyl groups so this will be the product of that alation reaction so how can we use a Gren re agent to make a primary alcohol a secondary alcohol and a tertiary alcohol so if you add a Gren reg agent to let's say like from alahh you're going to get a primary alcohol so the first thing that that happens is the grard attacks the Carbono group and a pi Bond breaks so we have a ch3 connected to a carbon that has an oxygen with a negative charge and and two hydrogen atoms at this point we can uh add H2O Plus or you can add water too but typically h2+ is added um to protonate oxide ion so this oxygen is going to grab a hydrogen and these electrons will return back to the oxygen so now we have ethanol which is a two carbon alcohol which we can also write like this so that's how you can make a primary aloh now if you want to make a secondary alcohol you need to add the grer re agent with an alahh that has at least one R Group so from aldah had two hydrogens but instead of the second hydrogen we now have like a carbon so the mechanism is the same so now we have this Alco oxideon and then the last step is protonation and so now we have a secondary alcohol whenever you add a grite reagent to like an alahh or Ketone um you can only add one R Group to make a tertiary alcohol we're going to add the grin reagent to a Keto so the mechanism is the same here is the R Group the methyl group that we added and then the last step is protonation using H2O plus so that's how you can make a tertiary alcohol use the Gren reaction now what if you want to make a carboxilic acid how can you do it so let's use ethyl magnesium bromide this time and what you want to do is react it with carbon dioxide the grin is going to attack the carbon and one of the double bonds is going to break so now we have three carbons instead of two so at this point we have the deprotonated form of the carboxilic acid so we can protonate it with aquous workup or just basically H2O plus and then it's going to pick up a hydrogen so now we have propanoic acid there's another way you can make a primary alcohol let's say if we use a Phenom magnesium bromide we can also add it to an epoxide this is going to attack the carbon and kick out an oxygen so now we have an Al oxide ion that is two carbons away um from the grard carbon and then if we add h3o+ we can get an alcohol now if we let's say if we wanted um a secondary alcohol instead of a primary we can modify the epoxide if we add a methyl group here the ch3 will be here and now we would have a secondary alcohol if you want to tertiary alcohol add another method group here and so there will be extra ch3 here and so now we'll be tertiary so you can control what type of um alcohol you get by modifying the substituents on the epoxide but now let's talk about synthesis reactions actually before that what's going to happen if we add a grin rage into an acid chloride now the difference between this reaction and what we considered before is that instead of adding one R Group we can add two so the first step is the same um that's the addition of the nucleophile to the carbonal group but now we have a leing group this time so this tetrahedral intermediate it's going to collapse it's going to turn into a ketone and it's going to kick out the chlorine so the first step is the acid chloride is reduced to a ketone and now once we have a ketone the grin reg agent won't stop there it's going to react with that Ketone and it's going to add another R Group now at this point we don't have a good leaving group there's no chloride to kick out so the only thing that's left to do is protonation we have to add H+ so now we have a tertiary alcohol but notice that we added um two methyl groups to this uh molecule so whenever you react to grard with an acid chloride or an ester you can add two R groups instead of one here's another example let's say if we use um cyoh hexom magnesium bromide and this time we're going to react with an Esther so like the acid chloride we can also add two R groups so the first step is the same we have an oxygen with a negative charge and here is our R Group that's the first one but now we have a not a terrible leing group but we do have a leing group this oxygen is going to reform a double bond and expel the methoxy group compared to other good leing groups it's not that great but it's still a leing group it's a poor leaveing group so this is our intermediate product but the grin agent won't stop there it's going to react with this Ketone and now we have the AL coxide Island again this time there's no leaving groups to kick out so now we have two R groups and Then followed by protonation now we have a tertiary alcohol so there's more than one way of making a tertiary alcohol you don't always have to use a ketone you could use an Esther or an A chloride the only difference is you're going to have two AR groups instead of one so now let's um go over some synthesis problem so let's say if you're given this alahh and you want to find the reagents that are necessary to transform it to this product how would you do it well notice that we need a secondary um alcohol and we have an alide so all we got to do really is add one R Group basically that's the only part that's different so whatever we see here is what we're going to add so we need five carbons 1 two 3 four five and a grer agent so 2 3 4 five and then mgbr that's step one step two is protonation h2+ so that's how we can find reagents needed to make that product let's try another example let's say if we have this particular Esther which two AR um can be added to it and let's say if we want to make this uh product notice the two AR groups that we have here so basically we need methyl magnesium bromide and then the last step will be h3o+ now what about this example actually instead of an alahh let's say if we're given an acid chloride and you want to know what Griner reagent you need um to make this particular tertiary alcohol how would you do it okay so clearly we see um the R groups that we need to add we need a five carbon ring and an mgbr group the last step is h2+ that's really what you have to do if you're trying to look for the grin re agent that you need to make that product but now you can get a synthesis question um that is presented to you in a different way so let's say if you're given the gred reagent and you need to find out what other compound you need to make this particular product how would you do it now if it's presented to you in this way it's a little bit harder because you have more options in the other example we just need a grin reagent we just got to find what carbon structure we need to add to our gr reagent but in this example um you need to know if you're using an alahh a ketone um an acid chloride an Esther an epoxide carbon dioxide you got to know which one so you really got to know your stuff but notice um we have five carbons in this structure now we have eight we need to add three carbons to it and we want the alcohol to be attached to the grard carbon whenever you see that typically you need like an alahh a ketone or maybe an ester or an acid chloride but the fact that we added one R Group rules out the acid chloride or the Esther so we need an aldhy or Ketone and the fact that it's a secondary alcohol means that we need an alahh so here is our alahh with three carbons 1 2 3 and then the second step will as always will be h3o+ so starting from the same um cyop pensom magnesium bromide reagent let's say if actually before that let's say if you have this isomer and you want to transform that product to an alkal chloride but you want um inversion of steroid chemistry what reagent would you need if you want to convert an alcohol to an uh a chlorine you need SO2 this reaction works by means of an sn2 reaction mechanism so the sterochemistry will invert from uh the front to the back sometimes these problems they don't stop with the alcohol and you may have need an additional step so I think it's good if I cover that now all right so starting from this cyop Pento magnesium bromide let's say if you want to make a primary alcohol instead of a secondary alcohol anytime you want to make a primary alcohol and the alcohol is well the carbon that has the alcohol is attached to the grer carbon if you only want to add one carbon the only thing you can use is form alahh followed by H2O plus now let's say if we want to convert that into an aloh haly what you could use is pbr3 this reaction also proceeds by means of an sn2 mechanism and it works well for uh primary and secondary alcohols but not tertiary alcohols so starting from the same reagent again let's say if you want to make a tertiary alcohol instead feel free to pause the video and try this one and me time I'm going to draw some other products okay so let's begin if you want to make the tertiary alcohol what reagent do you need so notice that um the alcohol is one carbon away from the granite carbon so we can use um a ketone or um we can't really use an acid chloride or an Esther the reason being is uh these R groups are different we have an ethyl and a propo so we have to use the Ketone the Ketone can contain those two R groups here's the ethyl part and here's the propy part followed by h2+ but now let's say if you want to make a primary alcohol and notice that it's two carbons away from the grin carbon how can you make that kind of alcohol well what you need is an epoxide it's going to add two carbons and it's going to give you the primary alcohol and then add H2 plus now let's say if you want to make a tertiary alcohol there's two ways you can do this but notice that actually three ways the two R groups are identical so number one we could use a symmetrical Ketone well actually that's what we have to use there's no other way if we use an a chloride or an Esther we're going to get this uh ring on we're going to get that ring twice so let's say if we have Phenom magnesium bromide and we wish to make these products feel free to try this on your own as well okay so if you need more time pause the video and just unpause it when you're ready so here we have a secondary alcohol a tertiary alcohol and a tertiary alcohol now notice that this secondary alcohol is two carbons away from the uh carbon that was from the grard carbon so this tells us that we need an epoxide however to get a secondary carbon we need to add this R Group to the epoxide and Then followed by h2+ so that's how we can make that compound now looking at the next one we have a tertiary alcohol which is two carbons away from the gr carbon so we need another epoxide but notice that attached to this carbon we have two R groups a methyl and an ethyl so here is the ethyl group and here is the methyl group followed by h2+ now how can we make this particular tertiary alcohol now one way we can do this is using a ketone as we've always done you can that always works but the Ketone has to have an ethyl group and and it has to be attached to a benzing ring that's one way we can do it but notice that we have two benzing rings whenever you see this you can also use an acid chloride or an Esther if you want to use the acid chloride this is the r group that the acid chloride has to contain and you simply need two equivalents of the Phenom magnesium bromide if you wish to use an Esther simply replace the chlorine group with like an ch3 or an O2 ch3 group this group won't matter much because it's going to leave just as the chlorine left so you can choose anything here but what's important is that you have these two carbon atoms on the Esther or on the acid chloride so you can use either a ketone acid chloride or an ester if you use a ketone make sure you have this um this fenel ring because the grenade will only add once to a ketone but twice to an acid chloride or an aster okay so let's try some more examples going back to this reagent find the reagents necessary to make this product and um this product as well as this product okay so if we want to make a carboxilic acid where it's attached to the grard carbon simply add carbon dioxide followed by h2+ now if you want to make a carboxilic acid that's one carbon away actually two carbons away from the uh grin carbon you need to use an epoxide first the epoxide followed by H2O plus will help you to get this primary alcohol that's two carbons away from the gred carbon once you have that primary alcohol you can oxidize it to a carboxilic acid using a very strong oxidizing agent this could be like chromic acid or you can use potassium perinate with H2O Plus or you can use like sodium D chromate with sric acid any one of these reagents will oxidize a primary alcohol to a carboxilic acid now if you want to get an alide two carbons away from the grin carbon simply use PCC and you can get that product so here's some more examples for you starting with this grener re agent go ahead and synthesize these comp compounds okay the first uh reaction is simply a direct alation reaction so all we need is those four carbons and an alcohal which we covered in the beginning of this video followed by h2+ now how can we make an alen basically a Cy Aline and a trans Al what we need to add to the grer reagent is an alkine but we also need a leing group like a bromine atom so we can connect the carbon bonds together so let's count the carbons that we need carbon 1 2 3 4 five six same thing here we need six carbons as well so first we need a bromine atom or like a chlorine and then this is carbon 1 2 3 4 5 six between carbons uh two and three we need an alkine a triple bond because from the triple bond we can get um the Cy and trans Aline so if we add this step followed by I'm not going to use h2+ because it can slowly react with the alkine I'm going to use water to proteinate the AL oxide so once we add these two initially we're going to get this uh product one two three four five six and a triple bond between two and three now from that product we can make the Cy or the trans Aline to make the cyst Aline you need to use hydrogen [Music] gas with the lender Catalyst to make the trans Aline you need to use sodium metal and liquid ammonia you can also use lithium metal as well both alkaline metals which are found in the First Column of the perct table they can both get the job done so that's it for the uh reactions of gred reagents and um I don't think you'll see anything extra compared to what we've covered you might see some other reactions actually you may see some ring closing examples so let's say if you have an acid chloride and you're able to get this gred reagent right next to it immediately those two are going to react now let's say if you have to not only predict a product but propose a mechanism um for that process how would you do it whenever you have um one part of the molecule reaction with another part of the same molecule it's going to close and form a ring so this Griner is going to attack the carbon nil group and that Bond's going to break so now if we count the carbons one two three four five we're going to have a five quiron structure so here we have an oxygen with a negative charge and we have a chlorine leaving group and the mgbr is somewhere in the solution once you add a Griner rent to something you don't have to worry about the mgbr part anymore this oxgen is going to reform a double bond and expel the chlorine group so this is the product that we're going to get for this reaction and we have the magnesium ion somewhere in the solution and the bromide and the chloride ion too so now let's say if let's see if you have this reagent and you add magnesium now there's many products that can form but draw two potential products that can form for this reaction one of which would be a cyclic reaction or an intermolecular reaction well we know first the Magnesium is going to uh attack carbon and expel the bromine ion so right now what we have is this and then mgbr now this Granite Regent could react with this carbon and expel the bromine atom so it can close and form a ring so we're going to count starting from where the Arrow begin to where it the carbon dated points to so we have a six carbon ring so let's say this is carbon 3 carbon 4 five six and therefore this is two and one um the reason why I chose to have carbon 3 on top is I want to put these two methyl groups on top carbon 4 has a methyl group and that's it so that's the product of this reaction now something else could happen as well this grer re agent could react with a separate molecule rather than reaction with itself so you can get some side products here here it can attack this carbon and expel the bromine atom and so these two chains can connect and this reaction could continue the grin re agent could react with another um similar molecule and this change can extend and who knows how long it can extend but we really shouldn't expect that this grenade will attack this carbon because that's going to be a very huge ring and 12 carbons it's possible but well that could be another side product so those are some products that you can get for this reaction okay last example for the day so let's say you have a benzing ring and let's say we have an alahh and a a bromine what's going to happen if we add magnesium to this compound well the first thing is that's going to happen is magnesium is going to uh create the grer agent so the carbon's attached to the magnesium and the bromide ion is paired up to to the Magnesium by an ionic bond so this is what we now have and now this grain of reagent is going to attack the alahh and the ring is going to close so starting from this carbon one two three four five six we're g to get a seven carbon ring you can count the other direction as long as you count from where the arrow pointed to where it ended or the other way around you'll get the same answer so now we have a seven carbon ring which we can draw like this so this is carbon 4 3 2 1 this is five 6 and carbon 7 7 has the oxygen with the negative charge the last thing we need to do is add h2+ and turn it into an alcohol now let's say if you want to convert that alcohol into an alen how can you convert an alcohol into an alen what reagents do you need to make that happen well you need to perform an E1 acid catalyzed reaction you can use phosphoric acid and heat 8 5% concentrated solution or you can use suric acid in heat as well both of these will remove the alcohol and create the alkan just in case if you want to make a alen from a Gren agent