Chemistry Reference
In-Depth Information
O
O
N
N
HH
HH
S
S
(Ph
3
P)
4
Pd
Ph
3
P
Ph
+
Ph
N
H
N
OAc
N
OAc
O
O
O
H
OO
9.249
9.250
Scheme 9.69
O
O
O
O
O
O
(Ph
3
P)
4
Pd
n
-BuCH(Et)CO
2
H
Bn
N
O
NHBn
-CO
2
O
N
Bn
O
O
O
H
9.252
9.251
Scheme 9.70
TBSO
TBSO
TBSO
H
Pd(PPh
3
)
4
,
THF
Grubbs II,
Ts O H
N
O
-CO
2
N
N
O
9.253
9.255
9.254
Scheme 9.71
CO
2
Et
CO
2
Et
O
O
1. Pd(OAc)
2
, PPh
3
2. H
3
PO
4
Et
Et
+
MeN
NMe
Et
O
N
Et
O
NH
2
.H
3
PO
4
O
AcHN
AcHN
9.256
9.257
Scheme 9.72
Similar reagents can be used for aloc-protected amines (Scheme 9.70);
95
in the absence of the competitive
nucleophile, the nitrogen undergoes allylation after decarboxylation, converting an allyl carbamate into an
allyl amine in an “allyl contraction”. This reaction, applied to carbamate
9.253
, was employed in a formal
synthesis of swainsonine when direct allylation was inefficient (Scheme 9.71).
96
An earlier part of this
synthesis can be found in Scheme 5.71.
Amines may be deallylated, as in the final step of a large-scale (29 g) preparation of tamiflu
R
9.257
(Scheme 9.72).
N
,
N
-dimethylbarbituric acid is often the competitive nucleophile of choice.
97
Additional
examples of amine deallylation can be found in Scheme 2.162 and Scheme 11.87.
