Chemistry Letters Vol.34, No.12 (2005)
1645
Table 3. Cyclizations of p-nitrobenzenesulfonamide and vari-
ous bisphosphinites by using 1-azidoadamantanea
XN
Ph2PO
OPPh2
NX
1-Azidoadamantane
Ph2PO
Ph2PO
(3.0 equiv.)
p-NsN
p-NsNH2
(1.0 equiv.)
Entry
1
2
1,2-Dichloropropane
2XN3
p-NsNH2
R
Ph2PO
80 °C, 6 h
(1.5 equiv.)
R
OPPh2
XN
Bisphosphinite
Product
Yield/%
Ph2PO
OPPh2
NX
X = 1-Adamantyl
1
2
84b
72
Ph2PO
Ph2PO
p-NsN
p-NsN
p-NsN
OPPh2
OPPh2
XHN
p-NsN
Ph2P O
OPPh2
NX
OPPh2
NX
H
Ph2PO
Ph2PO
OPPh2
OPPh2
3
4
5
6
75
82
77
84
p-NsNH
4
3
p-NsN
p-NsN
p-NsN
p-Ns
O
p-NsN
N
O PPh2
NHX
2
Ph2PO
Ph2PO
OPPh2
OPPh2
Ph2PNHX
S
S
O
S
O
S
5
Scheme 2.
p-Ns
Thus, it is noted that various nitrogen-containing cyclic
compounds are synthesized under neutral conditions by treating
bisphosphinites, easily prepared from diols with p-NsNH2 and
commercially-available 1-azidoadamantane. Further study on
this type of condensation reaction is now in progress.
N
70
Ph2PO
Ph2PO
7
OPPh2
OPPh2
p-Ns
N
51c
8
This study was supported in part by the Grant of the 21st
Century COE Program, Ministry of Education, Culture, Sports,
Science and Technology (MEXT), Japan.
p-Ns
N
54e,f
(67)g
9d
R
Ph2PO
S
S
R
OPPh2
aReactions were carried out on a 0.3 mmol scale. bWhen o-
NsNH2 was used, the corresponding pyrrolidine was obtained
in 89% yield. cWhen o-NsNH2 was used, the corresponding pyr-
rolidine was obtained in 47% yield. dDAICEL CHIRALPAK
AD-H column was used for HPLC analysis. eThe desired prod-
References and Notes
1
a) T. Shintou, K. Fukumoto, and T. Mukaiyama, Bull. Chem. Soc. Jpn.,
77, 1569 (2004). b) T. Shintou, W. Kikuchi, and T. Mukaiyama, Bull.
Chem. Soc. Jpn., 76, 1645 (2003). c) T. Mukaiyama, T. Shintou, and
K. Fukumoto, J. Am. Chem. Soc., 125, 10538 (2003).
T. Shintou and T. Mukaiyama, J. Am. Chem. Soc., 126, 7359 (2004).
T. Mukaiyama, K. Masutani, and Y. Hagiwara, Chem. Lett., 33, 1192
(2004).
28
2
3
uct was obtained with 94% de and >99% ee. ½ꢀꢂD ¼ þ30:0
28
f
(CHCl3, c1.20). ½ꢀꢂD ¼ ꢃ30:4 (CHCl3, c124) (preparation
from (2R,5R)-2,5-dimethyl pyrrolidine, p-NsCl and Et3N).
gBisphosphinite (2.0 equiv.) and 1-azidoadamantane (4.0 equiv.)
were used.
4
a) T. Mukaiyama and K. Ikegai, Chem. Lett., 33, 1522 (2004). b) K.
Ikegai, W. Pluempanupat, and T. Mukaiyama, Chem. Lett., 34, 638
(2005).
5
6
T. Mukaiyama and H. Aoki, Chem. Lett., 34, 142 (2005).
K. Masutani, T. Minowa, and T. Mukaiyama, Chem. Lett., 34, 1124
(2005).
H. Aoki, K. Kuroda, and T. Mukaiyama, Chem. Lett., 34, 1266 (2005).
For examples: a) T. Kan, A. Fujiwara, H. Kobayashi, and T.
Fukuyama, Tetrahedron, 58, 6267 (2002). b) D. V. Gribkov and
K. C. Hultzsch, Chem. Commun., 2004, 730. c) R. P. Wurz and
G. C. Fu, J. Am. Chem. Soc., 127, 12234 (2005).
a) Y. Tsuji, K. Huh, Y. Ohugi, and Y. Watanabe, J. Org. Chem., 50,
1365 (1985). b) Y. V. Subba Rao, S. J. Kulkarni, M. Subrahmanyam,
and A. V. Rama Rao, J. Org. Chem., 59, 3398 (1994). c) M. E.
Zwaagstra, A. Meetsma, and B. L. Feringa, Tetrahedron: Asymmetry,
4, 2163 (1993). d) S. Sumi, K. Matsumoto, H. Tokuyama, and T.
Fukuyama, Tetrahedron, 59, 8571 (2003).
A proposed mechanism is shown in Scheme 2: (2R,5R)-2,5-
dimethylhexanediyl bis(diphenylphosphinite) reacted initially
with 1-azidoadamantane to form the phosphinimidate, which
was in turn transformed to the phosphonium salt 3 by the inter-
action with p-NsNH2. A subsequence attack of the sulfonamide
anion to the carbon atom adjacent to an oxygen atom of the al-
koxy group afforded the compound 4 that has an N-alkyl sulfon-
amide and phosphinimidate groups in the same molecule. In a
similar fashion, deprotonation of 4 and the following intramolec-
ular nucleophilic attack took place to afford the corresponding
pyrrolidine.
7
8
9
10 Typical procedure is as follows; to stirred solution of 1,4-hexanediol
(10 mmol) and DMAP (3 mmol) in dry THF (50 mL) were added Et3N
(22 mmol) followed by ClPPh2 (21 mmol) under Ar atmosphere. After
stirring at rt for 3 h, TLC showed complete consumption of the alcohol,
and the resulted white slurry was concentrated by a rotary evaporator.
After the dilution of residue with hexane/EtOAc, the mixture was
filtered through a pad of alumina (activated, 300 mesh; purchased
from Wako Pure Chemical Industries, Ltd) and Celite. The filtrate
was concentrated under reduced pressure to give the desired bisphos-
phinite in 97%.
Typical experimental procedure is as follows: To a solution
of sulfonamide (0.3 mmol) and bisphosphinite (0.45 mmol) in
1,2-dichloropropane (0.6 mL) was added 1-azidoadamantane
(0.9 mmol) at 0 ꢁC under argon atmosphere. The reaction mix-
ture was stirred for an additional 6.0 h at 80 ꢁC. After completion
of the reaction (detected by TLC), the crude product was purified
by preparative TLC to afford the corresponding nitrogen-con-
taining cyclic compound.
Published on the web (Advance View) November 12, 2005; DOI 10.1246/cl.2005.1644