Organic Chemistry - Alcohol Synthesis Problem

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Discussion Overview

The discussion revolves around the synthesis of an alcohol from an alkyne, exploring various methods and reactions in organic chemistry. Participants share their approaches and reasoning related to hydration reactions, halide substitutions, and the conversion of alkynes to alkenes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests using a hydration reaction to convert an alkyne to an alcohol by mixing it with water.
  • Another participant proposes hydrating the alkyne and then substituting a hydroxyl group with a halide using PBr3, but later revises their suggestion, indicating a misunderstanding about the resulting structure.
  • A third participant outlines a multi-step process involving the conversion of the alkyne to an alkene using Na/liq.NH3, followed by the use of NBS to obtain allyl bromide, which is then reacted with aqueous NaOH to yield the desired alcohol.
  • Another participant believes that mixing an alkene with water could yield the desired alcohol, specifically mentioning the formation of 1,3-butanediol.

Areas of Agreement / Disagreement

Participants present multiple competing views on how to synthesize the alcohol, with no consensus reached on the best method. Some approaches are challenged or revised, indicating uncertainty in the proposed reactions.

Contextual Notes

Some participants express uncertainty about the accuracy of their chemical structures and reaction mechanisms, and there are indications of missing assumptions regarding the steps involved in the synthesis.

Who May Find This Useful

This discussion may be useful for students or practitioners in organic chemistry looking for various methods of alcohol synthesis from alkynes, as well as those interested in the nuances of reaction mechanisms and potential pitfalls in organic reactions.

tsaitea
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I have attached a file of the alcohol I need to synthesize and my futile attempt... I was thinking of using a hydration reaction to make the alcohol from the alkyne group. So basically I would mix the alkyne group with H2O and some how produce the alcohol group.

Am I heading in the right direction?
 

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It's been a while since I've done Ochem, but here's my suggestion. Hydrate the alkyne, substitute a hydroxyl group with a halide using an equimolar amount of a selective halide salt, like PBr3. The resulting aklene will be on the 1,2 position, and a antimarkovnikov addition of an alcohol should add an alcohol onto the 1 position, creating your desired substance.

By the way, you drew the alkyne incorrectly. It's always drawn in a straight line due to sp hybridization.

EDIT: Actually, what I said was wrong. I was thinking about it on the way to class, removal of the halide will result in the 2,3 alkene, the hydrogen on carbon 2 (the one with the hydroxyl group) will be removed. I'll think about this more.
 
Last edited:
Hi!

STEP 1: convert the alkyne to an alkene using Na/liq.NH3 .
STEP 2: Use NBS(N-Bromosuccinimide) to get allyl bromide(CH3CH=CHCH2Br) which when reacted with aq.NaOH gives alcohol(CH3CH=CHCH2OH).
STEP 3: Acidic hydrolysis of this alcohol gives the required product.

Vineeth.
 
You're looking to form 1, 3 - butanediol I believe. I'm pretty sure you can mix an alkene with water to get an alcohol.

My organic chem is a bit rusty, but I believe (1 - hydroxy - 2 - butene) + H - OH should give you what you're looking for.
 

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