Synthesis of β-Vetivone More resources available ... - ChemistforChrist

Synthesis of β-Vetivone
For the real system:
EtO
O
1. Ac 2O
2, BF 3
by elimination
of the tert-alcohol
O
1. NaH
2.
O
EtO H
EtO
EtO
Synthesis of Büchi JOC 1976, 41, 3208
H
H
pKa = 15
base
O
O
OH
O
H
MeLi
NaH
EtO
This double bond formed
due to being the most stable
one (4 Subst instead of 3)
H
O
R H
EtO
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O
O
H
Only this enantiomer shown,
to explain diasteroselectivity
of the reaction.
O
OH
H
R
The Fuchs synthon comes in anti in regard to
the methyl group.
CO 2Et
- H 2O
PPh 3
CO 2Et
H 2 / Pd
EtO
EtO
O
Ph 3P
O
CO 2Et
O
Wittig
H
CO 2Et
This double bond
is more e - poor than the
other one (even though the
difference might not be that
big)
Fulvenes
Fulvenes can react as a micheal acceptor. The driving force of the reaction is the creation of an aromatic
system:
Nu
R
For example: Nu = R 2CuLi (Cuprates)
R
Nu
6 π-electron
System
R