Jasmone 1 - ChemistforChrist

Synthesis of JASMONE
Another way to see it is:
Bn
HO
N
S
A nucleophilic Carbene
This kind of carbenes are pretty important today:
Ar The first carbene that was isolated, crystalized and characterized.
N Today there are many chiral versions available that are used
in asymmetric synthesis.
N
Ar
N
N
Ar
Ar
Very reactive
species! Prone
to nucleophilic
attack.
N
N
Nu
H
N
N
N
N
Ar
Ar
6-π Electron aromatic
system, that's why the carbene
is so stable!
Idea:
Block the site prone
to nucleophilic attack
with very bulky substituents.
The 2 plane where the 2 mesityl
substituents are lying in are
perpendicular to each other.
More resources available at
www.chemistforchrist.de
Putting different charges on the
same carbon atom can also be a
way of representing a carbene!
N
N
N
N
Mesityl- Adamantyl-
The fact that carbenes can be used in catalysis as a Ligand is due to the fact that the 2 Electrons in the sp 2
Orbital behave like lone pair and can thus donate electron density to the corresponding metal.
R
N
N
R
behaves like a
Donor e.g.
R
R P
R
Carbenes in catalysis are often named NHC-Ligands (N-Heterocyclic Carbenes) and offer many advantages
compare to their Phosphorous counterparts:
a) Environmentally more friendly (often non toxic)
b) Not sensitive to oxidation
c) Lower Molecular mass, for industrial purpose this means less gramms or kg of Ligand has to be added.