Chemistry Reference
In-Depth Information
R
1
R
1
R
1
Bn
Bn
Bn
(COCl)
2
-DMSO
N
N
N
reductio
n
O
OR
HO
OR
OR
MeOOC
1817
1815
1816
R = benzyloxymethyl,
tert
-butyldiphenylsilyl
R
1
= Boc, COOCH
2
Ph
Bn = benzyl
oxalyl chloride/DMSO in the presence of DIPEA to give aldehydes 1820 in 77-96%
yield [1383].
R
e
LiBH
4
R
2
OH
R
CHO
(COCl)
2
-DMSO
NBoc
NBoc
NBoc
O
O
O
DIPEA
77-96 %
1818
1819
1820
R = H, Me
Boc = Me
3
COCO
Oxidation of protected hydroxynorleucine derivatives 1821 gives the corresponding
aldehyde 1822, which is amenable to further transformations, opening a versatile
synthetic route for the generation of C-7 substituted azepinones [1326].
COOR
1
COOR
1
(COCl)
2
-DMSO
PhtN
OH
PhtN
O
1821
1822
Pht = phthalimido
R
1
= Me, Bn
Nitrohydroxylated pyrrolidine and piperidine ring systems 1824 have been con-
veniently obtained by a one-pot procedure involving sequential Michael-Henry re-
action between nitroethene and a nitrogen nucleophile 1823 suitably predisposed
for the oxidative generation (Swern reaction) of an aldehyde group, which is di-
rectly trapped in the subsequent nitroaldolization step [1384].
HO
NO
2
1)
NO
2
HO
N
H
Ph
N
n
n
2) Swern oxidation
Ph
n = 1, 2
1823
1824
