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[tonykangus]

Anyone can help me out.

What is final product after step 1) through 4)?

Cycloheane-CH2OH

1)PCC/CH2Cl

2)NaCN/HCN

3)LiAlH4/Et2O

4)H2O

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[harrygt]

Anyone can help me out.

What is final product after step 1) through 4)?

Cycloheane-CH2OH

1)PCC/CH2Cl

2)NaCN/HCN

3)LiAlH4/Et2O

4)H2O

Nice question: Let's go one by one:
after step 1: cyclohexane- CHO [aldehyde]
after step 2: cyclohexane - C(OH)CN [cyanohydrin]
after step 3 and 4 : cyclohexane - C(OH)CH2NH2 [LiAlH4/H2O reduced the CN to CH2-NH2

Final answer: Cyclohexane - CH(OH)CH2NH2
I hope this helps

 

[DRHOYA]

Nice question: Let's go one by one:
after step 1: cyclohexane- CHO [aldehyde]
after step 2: cyclohexane - C(OH)CN [cyanohydrin]
after step 3 and 4 : cyclohexane - C(OH)CH2NH2 [LiAlH4/H2O reduced the CN to CH2-NH2

Final answer: Cyclohexane - C(OH)CH2NH2
I hope this helps

I followed your reasoning and that actually helped me out too. So for step 1 PCC takes the primary alcohol to the aldhyde (now on the ring). Then step 2 the C=O goes away and becomes a C bonded to an OH group, the CN group, and H, and the CH2 from the ring (Is this an acetal??). Ok, then steps 3 and 4, since LiAlH4/H2O is a reducer, the CN gets reduce dto NH2.......so the final product is the ring......with CH2 then a C bonded to an OH, an H, and an NH2.

I hope I just understood that and didn't make a fool of myself.

 

[harrygt]

I followed your reasoning and that actually helped me out too. So for step 1 PCC takes the primary alcohol to the aldhyde (now on the ring). I don't get what you exactly mean by saying "Now in the ring". At this point, we have a ring connected to a carbon which has a double bond with O and a single bond with H. [aldehyde]. I guess you meant this too.


Then step 2 the C=O goes away and becomes a C bonded to an OH group, the CN group, and H, and the CH2 [CH not CH2] from the ring (Is this an acetal??). No, acetal is when you have two OR groups connected to a carbon through their oxygens. There is no Or group in this molecule.

Ok, then steps 3 and 4, since LiAlH4/H2O is a reducer, the CN gets reduce dto CH2 - NH2.......so the final product is the ring......with CH2 then a C bonded to an OH, an H, and an NH2. Nope, the final product is a ring connected to a C which is connected to OH, H and CH2NH2[from the CH2 side]

I hope I just understood that and didn't make a fool of myself.

Good try. Good try! You just made a few mistakes, but it's good to know that LiAlH4 reduces -CN to -CH2NH2.

 

[tonykangus]

Good try. Good try! You just made a few mistakes, but it's good to know that LiAlH4 reduces -CN to -CH2NH2.

I can usnderstand now. I did not know LiAlH4 reduces -CN to -CH2NH2. I thought LiAlH4 reduces the Ring-alcohol -CH ( Ithought secondry alocohal make ketone)only.

 

[DRHOYA]

Good try. Good try! You just made a few mistakes, but it's good to know that LiAlH4 reduces -CN to -CH2NH2.

Ok thanks. I think my wording was worse than it sounds. My question is.....when you start you have a ring then a CH2OH bonded to it. PCC reduces that to a ring with C=O on it. Then you get that same C, but not more double bond as the CN comes on (C bonded to OH, CN, ring and H) Ok, then the final product after the reduction is the ring--CH2---NH2.

 

[harrygt]

Ok thanks. I think my wording was worse than it sounds. My question is.....when you start you have a ring then a CH2OH bonded to it. PCC reduces that to a ring with C=O on it. Then you get that same C, but not more double bond as the CN comes on (C bonded to OH, CN, ring and H) Ok, then the final product after the reduction is the ring--CH2---NH2.

you made another mistake. the final product is gonna be ring--CH(OH)--CH2--NH2.
The once you wrote is missing a carbon [connected to OH, H, Ring and CH2NH2. GOt it?]

 

[DRHOYA]

Yeah. Looks like I can't count carbons lol. Hopefully with a pic I would have answered correctly.