Gilman Reagent

Organocopper reagent High order cuprates

1. GILMAN REAGENT
Presented to :-Dr. DharminderSharma
Presented By :-Manish Kumar
Roll No. 4857
M.Sc. Chemistry(4
th
sem)
Practical code :-CH-526
Date :-17 June, 2021

2. Introduction:
•Gilman reagent also known as organocopperreagents.
•Organocopperreagents are prepared by transmetallatingthe
organomagnesium, organolithiumor organozincreagent with copper(I) salts.
•reactivity of organocuprateswith electrophiles follows the order:
RCOCl> R-CHO > R-OTs > R-I > R-Br > R-Cl > RCOR > R-CO2R' R-CN > RCH=CH2
R = alkyl, aryl or heteroaryland can have remote functionaliytsuch as
ethers, aetalor ketals

3. The Common Reaction Of Gilman Reagent:
1) Reactions with Acid Chlorides 2) Coupling Reactions
3) Conjugate Addition 4) Reactions with Aldehydes and Ketones
5) Reactions with Epoxides
Reactions With Acid Chloride: The reaction of a dialkylcuprateand acid chloride
is a preferred method to synthesize ketones. Unlike in the case of Grignard
reagents, the ketones formed do not react with organocopperreagent.

4. Coupling Reactions:-Organocupratescan replace halide ion from primary and
secondary alkyl halides to give cross-coupled products. This method provides
effective route for the construction C-C bond between two different alkyl halides,
which is not possible by the well known Wurtzcoupling reaction, in which a
number of products are formed.
Similar results are obtained from the reactions of aryl halides and organocuprates

5. ConjucateAddition Reaction:
The organocopperreagents are softer than Grignard
reagents (because copper is less electropositive than magnesium), and add in conjugate
fashion to the softer C=C double bond.
•The mechanism of the transfer of the alkyl group from the organocupratesto the β-position
of the carbonyl compounds is uncertain. It is believed that initially a d-π* complex between
the organocopper(I) species and the enoneis formed followed by the formation of a Cu(III)
intermediate which may undergo reductive elimination to form the product.

6. In the case of enones, consecutive addition of the organocopperreagent and alkyl halides,
two different alkyl groups can be introduced in one operation.

7. Reactions With Aldehyde And Ketone:
Organocupratesreact with aldehydes to give
alcohols in high yield (Scheme 8). In the presence of chlorotrimethylsilane, the corresponding
siliylenolethers can be obtained.

8. Reactions With Epoxide:
The epoxide is attacked by organocopperreagents at the least
substituted carbon atom giving the corresponding alcohol.
In disubstitutedepoxide inversion of configuration occurs in the ring carbon because reaction
is SN2 reaction.
O HH
OH
H
H
Ph Ph
Ph
Ph
CH
3
CuLi
H
2
O/H
+

9. High Order Cuprates
: Cupratesare useful but there are a few problems associated with
them. To overcome these limitations, Lipshutzdeveloped higher order mixed cuprates,
R2Cu(CN)Li2, by the reaction of organolithiumreagent with cuprous cyanide.
2R-Li + CuCN R2Cu(CN)Li2
Higher order cupratesshow greater reactivity compared Gilman reagents with alkyl halides,
even secondary halides. For example, (S)-2-bromooctane reacts with EtMeCu(CN)Li at 0 oCto
give (R)-3-methylnonane in 72% yield

10. Thank you