Jun 25, 2011
105
2
Nevada
Status
Pre-Dental
View attachment 6057234508_f78487772a.jpg

Is this right? I don't know if I'm drawing a blank but I've never seen the first reaction happen before! Can you use a nucleophile to replace something on the ring? Or does it just happen with organolithium compounds?

Also for the second question, why doesn't CrO3 oxidize the alcohol all the way to form a carboxylic acid?
 
Jul 26, 2011
729
1
New York
Status
Dental Student
I've seen CuLi(CH3)2 used in conjugated ketones where only one methyl of the two will be attached to the substrate... but I guess it could work for electrophilic aromatic substitution

2nd one works. CrO3 is same thing as PCC

PCC stands for pyridinium chloromate - a mixture of CrO3/H+/pyridinium

However, don't get fooled because K2Cr2O7 will take primary alcohol all the way to carboxylic acid
 
Jun 25, 2011
105
2
Nevada
Status
Pre-Dental
I've seen CuLi(CH3)2 used in conjugated ketones where only one methyl of the two will be attached to the substrate... but I guess it could work for electrophilic aromatic substitution

2nd one works. CrO3 is same thing as PCC

PCC stands for pyridinium chloromate - a mixture of CrO3/H+/pyridinium

However, don't get fooled because K2Cr2O7 will take primary alcohol all the way to carboxylic acid
Oh duhh... lol I guess it's because I'm used to seeing only the letters PCC and not its actual formula. Thanks!

And for #1, I figured it out. It's actually a benzyne reaction (elimination-addition) with chlorine as a leaving group. In case anyone wants to know this: Organolithium is actually a strong base (although it's a "soft" nucleophile") and pulls off a H right next to chlorine which leaves as a LG, to make a benzyne. The benzyne can then attack a CH3 from (CH3)2CuLi. I remember covering this in my ACS review book. One thing I'm not sure about though is why there is a nitro group on the ring. Nitro groups ortho/para to a Cl leaving group will undergo (addition-elimination) nucleophilic aromatic substitution....but whatever lol it's good enough.

back to studying..
 
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