Chemistry Letters Vol.33, No.10 (2004)
1299
1) TMSCl
2) LiHMDS
3) LDA
employed instead of 15 yellowish product 10 was obtained only
in 30% yield.
+
OHC
SO2Ph
THF
N
N
In summary, the double elimination protocol has proved to
be effective for synthesis of pyridylacetylenes.
N
N
12 48%
11
2
1) BuLi
2) 14
3) ClP(O)(OEt)2
4) LiHMDS
Financial support from New Energy and Industrial
Technology Development Organization (NEDO) of Japan for
Industrial Technology Research Grant Program (01B68006d)
and the Sumitomo Foundation to A. O. is gratefully acknowl-
edged.
+
12 83%
SO(=NTs)Ph
OHC
THF
N
N
14
13
Scheme 3.
TMS
Pd(PPh3)4
CuI
1) BuLi
2) DMF
3) HCl
References and Notes
1
K2CO3
17 98%
a) C. A. Schalley, A. Lutzen, and M. Albrecht, Chem.—Eur.
¨
THF
Br
OHC
N
Br
N
OHC
N
78%
Br
J., 10, 1072 (2004). b) C. Tschierske, Angew. Chem., Int.
Ed., 39, 2454 (2000). c) J.-M. Lehn, Chem.—Eur. J., 6,
2097 (2000).
TMS
C6H13
95%
I
TMS
Pd(PPh3)4
CuI
2
3
a) T. Kawano, T. Shinomaru, and I. Ueda, Org. Lett., 4, 2545
(2002). b) T. Kawano, J. Kuwana, T. Shinomaru, C.-X. Du,
and I. Ueda, Chem. Lett., 2001, 1230.
Pd(PPh3)4
CuI
K2CO3
18 91%
Br
N
Br
N
Br
73%
a) X. Shen, T. Moriuchi, and T. Hirao, Tetrahedron Lett., 44,
7711 (2003). b) A. Khatyr and R. Ziessel, Tetrahedron Lett.,
43, 7431 (2002). c) H. S. Joshi, R. Jamshidi, and Y. Tor,
Angew. Chem., Int. Ed., 38, 2722 (1999). d) V. Balzani, A.
Juris, and M. Venturi, Chem. Rev., 96, 759 (1996).
a) F. Ye, A. Orita, A. Doumoto, and J. Otera, Tetrahedron,
59, 5635 (2003). b) A. Orita, F. Ye, A. Doumoto, and
J. Otera, Chem. Lett., 32, 104 (2003).
OHC
N
17
Pd(PPh3)4
CuI
N
OHC
N
+
4
C6H13
16 74%
Br
N
18
C6H13
5
6
A. Orita, D. Hasegawa, T. Nakano, and J. Otera, Chem.—
Eur. J., 8, 2000 (2002).
a) D.-L. An, T. Nakano, A. Orita, and J. Otera, Angew.
Chem., Int. Ed., 41, 171 (2002). b) A. Orita, D. Hasegawa,
D.-L. An, T. Nakano, J. Yaruva, N. Ma, and J. Otera,
Chem.—Eur. J., 8, 2005 (2002).
Scheme 4.
SO(=NTs)Ph
N
+
OHC
N
SO(=NTs)Ph
7
8
A. Orita, T. Nakano, D.-L. An, K. Tanikawa, K. Wakamatsu,
and J. Otera, J. Am. Chem. Soc., 126 10389 (2004).
To a THF solution (3 mL) of disulfoxime 15 (213.9 mg,
0.20 mmol) was added BuLi (0.33 mL, 1.35 M hexane solu-
tion, 0.46 mmol) at À78 ꢀC, and the mixture was stirred for
0.5 h. To this solution was added a THF solution (3 mL) of
16 (164.8 mg, 0.42 mmol), and the mixture was stirred for
1.5 h. After ClP(O)(OEt)2 (0.064 mL, 0.44 mmol) had been
added, the reaction mixture was stirred at RT for 2 h. After
lithium hexamethyldisilazide (3.0 mL, 1.0 M THF solution,
3.0 mmol) had been added at À78 ꢀC, the mixture was stirred
at À78 ꢀC for 1 h and at RT for 1 h. After usual workup with
sat. NH4Cl aq/CH2Cl2, the combined organic layer was
washed with brine and dried over anhydrous soudium sul-
fate. The organic layer was evaporated under vacuum, and
the residue was subjected to column chromatography to give
10 (130.1 mg, 53%).
C6H13
16
15
1) BuLi
2) 16
C6H13
3) ClP(O)(OEt)2
4) LiHMDS
N
N
N
N
THF
C6H13
10 53% white powder
Scheme 5.
ously reported.6b A pyridylcarboxaldehyde 16 was accessible by
repeating the Sonogashira coupling as shown in Scheme 4.
The aldol-type coupling between an enantiopure disulfox-
imine 15 and pyridylcarboxaldehyde 16 followed by double
elimination of the resulting ꢀ-substituted sulfoximine furnished
the desired acetylene 10 in 53% yield (Scheme 5).8 Notably, the
product thus formed suffered from no coloration and enjoyed
facile purification. When the corresponding disulfone was
Published on the web (Advance View) September 11, 2004; DOI 10.1246/cl.2004.1298