Good day from Chem Help ASAP.
Let’s open up the definition of organometallics.
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In introductory organic chemistry, the most
commonly encountered organometallic reagents
are Grignard and organolithium reagents.
These two organometallics are prominent because
the carbon atoms in these reagents are extremely
nucleophilic.
In fact, you can use these reagents, especially
the organolithium reagents, to make other
organometallic reagents built around other
metals.
On the slide we have, on the left, the same
organolithium reagent – phenyllithium – drawn
as an ionic structure.
A carbanion and a lithium cation.
In each case, we react phenyllithium with
a different metal salt.
In the first reaction, we react phenyllithium
with zinc chloride.
I’ll show a mechanism, which may be a fantasy,
but the product
has a carbon-zinc bond (shown as a covalent
bond).
This is an *organozinc* reagent.
In the second reaction, we react phenyllithium
with trimethyltin chloride.
This makes an *organotin* reagent.
(If you want to be picky, trimethyltin chloride
already has carbon-tin bonds and is also an
organotin reagent.)
In the bottom reaction, we react phenyllithium
with copper chloride.
This reaction is a little bit different.
This reaction requires twice as much phenyllithium
as the copper salt.
So, that’s a partial mechanism.
The product has two phenyls on the copper.
The copper formally has a negative charge.
Lithium balances the negative on copper.
A side product is lithium chloride.
This is an *organocopper* reagent, sometimes
called a *cuprate*.
All these new organometallic reagents are
less nucleophilic than organolithium reagents
and yet have found different uses in the world
of organic synthesis.
The conversion of one organometallic reagent
(like an organolithium reagent) to another
organometallic reagent is called a *transmetallation*.
Transmetallations are great for accessing
a new carbon-metal bond, which also allows
access to completely different types of chemical
reactivity.
Organometallic chemistry, as a field, is less
thoroughly explored than organic chemistry
and frequently enjoys new, groundbreaking
discoveries.
