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This δ size 12{δ - {}} {} carbon consequently has significant nucleophilic character. The Grignard reagent reacts well as a nucleophile with the δ + size 12{δ+{}} {} -carbon of the carbonyl group as a target. The C=O π-bond is broken and the carbonyl becomes an alcohol. In the process, a new carbon-carbon bond is formed between the Grignard reagent and the carbonyl carbon - now the alcohol carbon.

The intermediate alkoxymagnesium salt is neutralized by acid in the work-up to produce the alcohol product. Before we go on to look at more Grignard reactions with carbonyl groups, here is a problem for you to try.

  • Identify the product (A-E) (5 points)


Addition of GR to carbonyls:

GR adds to a carbonyl compounds to generate alcohols. A more modern interpretation extends the scope of the reaction to include the addition of Grignard reagents to a wide variety of electrophilic substrates:

Depending upon the amount of GR used and the substrate, it can give different types of products after working up the reaction. Here is an example:

Addition of GR to α, β unsaturated carbonyls:

GR adds to carbonyl center mainly in two fashions. Alkyl lithium halides add only in 1, 2-fashion because R-Li is a more reactive organometallic compound than others, so it prefers to add to most HARD carbonyl carbon center (since it is more electrophilic in nature). On the other hand, R 2 CuLi size 12{R rSub { size 8{2} } ital "CuLi"} {} or R MgX / Cu 2 + size 12{R - ital "MgX"/ ital "Cu" rSup { size 8{2+{}} } } {} adds only in 1,4- fashion, because C-4 is soft towards electrophilicity and soft cuprate reagents prefer to add only to soft centers according to HSAB (Hard Soft Acid Base ) theory. Traditional GR (alkyl magnesium halide) is intermediate in its’ reactivity, so a mixture of 1, 2- and 1, 4- addition product is obtained. Here is an example of a GR adding to a α, β unsaturated carbonyl compound:

Most alcohols can be produced by a Grignard reaction. In deciding how to do this carry out the reaction, think about the Grignard reaction in reverse: if your target alcohol had been the result of a Grignard reaction, what would the carbonyl compound have to be? What would the Grignard reagent have to be?

Consider the scheme below for the synthesis of 1-phenyl-1-butanol via a Grignard reaction. Two different ways to synthesize this compound are shown. Can you think of a third?

Important facts:

Grignard reagent (RMgX) is a very polar reagent and a very strong Lewis base and therefore will be easily protonated by water, which acts as a strong acid when in contact with a Grignard reagent. The reagent’s reaction with water produces a gelatinous metal hydroxide. Since it reacts rapidly with the acidic hydrogen atom, the reaction must be carried out under dry conditions since even a small amount of moisture can destroy the reagent. The reactivity of Grignard reagent depends on mainly two factors:

1. Types of metal center (Li>K>Mg etc)

2. Types of halides present (I>Br>Cl) and

3. Types of solvent used.

In presence of different functional groups, the order of reactivity of GR is as follows:

Our experiment:

In this experiment, the addition of a nucleophilic Grignard reagent (1-methylbutylmagnesium bromide), to the electrophilic carbonyl carbon of an aldehyde (propanal) is performed.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
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sure. what is your question?
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I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
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algebra 2 Inequalities:If equation 2 = 0 it is an open set?
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or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
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Kristine 2*2*2=8
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Differences Between Laspeyres and Paasche Indices
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No. 7x -4y is simplified from 4x + (3y + 3x) -7y
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is it 3×y ?
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J, combine like terms 7x-4y
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linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
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after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
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silver nanoparticles could handle the job?
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Chem217labsfall07. OpenStax CNX. Oct 16, 2007 Download for free at http://cnx.org/content/col10463/1.4
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