266
ORGANIC SYNTHESIS—1995
IV.G-16 Clark, R.D., Jahangir and Langston, J.A., CJC, 72, 23.
.Me
Χ^χ^ ^ Ν ^ ^ΟΗ
sBuLi, DMF
NHBoc
THF, -20°
Boc
60-97%
IV.G-17 Katritzky, A.R. et al., JOC, 59, 4556; see also: Molina, P. et
al., TU 35, 1453 and 8851; Neidlein, R., Suschitzky, H. et al., JCS(Pl),
9 Al.
ff
(C 2 H s O) 2 P^ Λί.
V
a
CHO
PPh,
CHO
similar cyclizations involving iminophosphoranes 55%
IV.G-18 Walter, H., HCA, 77, 608; Linken, F. and Laschat, S., SL, 125;
Nitta, M. et al., JOC, 59, 1309; Fujiwara, H. and Okabayashi, I., CPB, 42,
1322 and H, 38, 541.
O
?
X
IJL
TsOH,to.,A
N'
40-96%
H
Me
R 2
IV.G-19 Reuter, D.C., Flippin, L.A. et al., TL, 35, 4899.
JU
t , B u L i
2. TFA, CH 2 C1 2
21-74% R 3 "
ORGANIC SYNTHESIS—1995
IV.G-16 Clark, R.D., Jahangir and Langston, J.A., CJC, 72, 23.
.Me
Χ^χ^ ^ Ν ^ ^ΟΗ
sBuLi, DMF
NHBoc
THF, -20°
Boc
60-97%
IV.G-17 Katritzky, A.R. et al., JOC, 59, 4556; see also: Molina, P. et
al., TU 35, 1453 and 8851; Neidlein, R., Suschitzky, H. et al., JCS(Pl),
9 Al.
ff
(C 2 H s O) 2 P^ Λί.
V
a
CHO
PPh,
CHO
similar cyclizations involving iminophosphoranes 55%
IV.G-18 Walter, H., HCA, 77, 608; Linken, F. and Laschat, S., SL, 125;
Nitta, M. et al., JOC, 59, 1309; Fujiwara, H. and Okabayashi, I., CPB, 42,
1322 and H, 38, 541.
O
?
X
IJL
TsOH,to.,A
N'
40-96%
H
Me
R 2
IV.G-19 Reuter, D.C., Flippin, L.A. et al., TL, 35, 4899.
JU
t , B u L i
2. TFA, CH 2 C1 2
21-74% R 3 "