Y. Demizu et al. / Tetrahedron Letters 50 (2009) 5241–5244
5243
Table 3
Kinetic resolution of various
a
-hydroxyalkanephosphonates DL-3a–oa
BzCl (0.5 equiv)
Cu(OTf) 2 (0.05 equiv)
(R,R)-Ph-BOX (0.05 equiv)
BaCO3 (1.0 equiv)
OH
OBz
OH
OEt
OEt
OEt
OEt
OEt
OEt
R2
P
R2
P
R2
P
+
Chlorobenzene
0 °C to rt, 12 h
O
O
O
DL-3a−o
(R)-4a−o
(S)-3a−o
Recovered (S)-3a–o
Entry
Substrate
R2
Product (R)-4a–o
s
Yield (%)
eeb (%)
Yield (%)
eeb (%)
1
2
3
4
5
3a
3b
3c
3d
3e
3f
Me
Et
n-Pr
(E)-MeCH@CH
Ph–C„C
i-Pr
i-Pr
i-Bu
Cyclohexyl
Ph
ClCH2
BnO–(CH2)2
Cbz-NH–(CH2)2
Boc-NH–(CH2)2
BnO–(CH2)3
2-Furyl
(R)-4a
(R)-4b
(R)-4c
(R)-4d
(R)-4e
(R)-4f
(R)-4f
(R)-4g
(R)-4h
(R)-4i
(R)-4j
(R)-4k
(R)-4l
(R)-4m
(R)-4n
(R)-4o
37
26
28
18
45
40
52
20
32
Trace
35
30
13
29
80
88
>99
>99
42
84
74
94
88
—
92
95
81
94
88
66
(S)-3a
(S)-3b
(S)-3c
(S)-3d
(S)-3e
(S)-3f
(S)-3f
(S)-3g
(S)-3h
(S)-3i
(S)-3j
(S)-3k
(S)-3l
(S)-3m
(S)-3n
(S)-3o
47
56
68
73
47
60
47
64
67
>99
63
65
71
55
53
56
65
47
37
27
41
50
87
32
42
—
55
39
7
40
46
24
18
25
286
259
4
19
32
44
24
—
42
57
10
48
25
6
6
7c
8
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
9
10
11
12
13
14
15
16
27
38
a
DL-3a–o (0.5 mmol), Cu(OTf)2 (0.025 mmol), (R,R)-Ph-BOX (0.025 mmol), BzCl (0.25 mmol), BaCO3 (0.5 mmol) in chlorobenzene (3.0 mL) at 0 °C to rt for 12 h.
Determined by HPLC.
BzCl (0.35 mmol) was used.
b
c
11803; (d) Kim, D. Y.; Wiemer, D. F. Tetrahedron Lett. 2003, 44, 2803; (e) Saito,
B.; Egami, H.; Katsuki, T. J. Am. Chem. Soc. 2007, 129, 1978; (f) Qiu, M.; Hu, X.-P.;
Huang, J.-D.; Wang, D.-Y.; Deng, J.; Yu, S.-B.; Duan, Z.-C.; Zheng, Z. Adv. Synth.
Catal. 2008, 350, 2683; (g) Abell, J. P.; Yamamoto, H. J. Am. Chem. Soc. 2008, 130,
10521; (h) Uraguchi, D.; Ito, T.; Ooi, T. J. Am. Chem. Soc. 2009, 131, 3836.
2. Kaboudin, B. Tetrahedron Lett. 2003, 44, 1051.
Kinetic resolution of various
DL-3a–o by benzoylation under the optimized reaction condi-
tions14 is summarized in Table 3.15 Straight-chained
-hydroxy-
a-hydroxyalkanephosphonates
a
alkanephosphonates 3a–d were benzoylated to afford the corre-
sponding optically active (R)-4a–d in moderate yields and with
good to excellent enantioselectivities (entries 1–4), while pheny-
lethynylated alcohol 3e gave benzoylated product 4e with low s
value of 4 (entry 5). Compounds 3f–h with branched chained
groups were kinetically resolved with good to high s values (entries
6–9), while benzoylation of phenyl-substituted alcohol 3i did not
proceed to afford the corresponding benzoate 4i (entry 10).
Straight carbon-chained compounds 3j terminally functionalized
with Cl atom, 3k and 3n with benzyloxy group gave high s values
of 42, 57, and 25, respectively (entries 11, 12, and 15). N-Boc-ami-
noethylated alcohol 3m was kinetically resolved with high s value
of 48 (entry 14), while N-Cbz-protected one 3l fell short in terms of
yield and enantioselectivity (entry 13). Compound 3o substituted
with 2-furyl group gave low s value of 6 (entry 16). Using 0.7 equiv
3. Recent literatures for kinetic resolution of
a-hydroxyalkanephosphonates by
enzymatic methods: (a) Zhang, Y.; Yuan, C.; Li, Z. Tetrahedron 2002, 58, 2973;
(b) Pàmies, O.; Bäckvall, J. E. J. Org. Chem. 2003, 68, 4815; (c) Wang, K.; Zhang,
Y.; Yuan, C. Org. Biomol. Chem. 2003, 1, 3564.
4. Mono-benzoylation: (a) Matsumura, Y.; Maki, T.; Murakami, S.; Onomura, O. J.
Am. Chem. Soc. 2003, 125, 2052; (b) Matsumura, Y.; Maki, T.; Tsurumaki, K.;
Onomura, O. Tetrahedron Lett. 2004, 45, 9131; Mono-carbamoylation: (c)
Matsumoto, K.; Mitsuda, M.; Ushijima, N.; Demizu, Y.; Onomura, O.;
Matsumura, Y. Tetrahedron Lett. 2006, 47, 8453; Mono-tosylation: (d)
Demizu, Y.; Matsumoto, K.; Onomura, O.; Matsumura, Y. Tetrahedron Lett.
2007, 48, 7605.
5. Mitsuda, M.; Tanaka, T.; Tanaka, T.; Demizu, Y.; Onomura, O.; Matsumura, Y.
Tetrahedron Lett. 2006, 47, 8073.
6. Tosylation of a-hydroxyalkanamides: (a) Onomura, O.; Mitsuda, M.; Nguyen, T.
T. M.; Demizu, Y. Tetrahedron Lett. 2007, 48, 9080; Benzoylation and tosylation
of b-hydroxyalkanamides: (b) Demizu, Y.; Kubo, Y.; Matsumura, Y.; Onomura,
O. Synlett 2008, 433.
7. Asymmetric oxidation of 1,2-diols: (a) Onomura, O.; Arimoto, H.; Matsumura,
Y.; Demizu, Y. Tetrahedron Lett. 2007, 48, 8668; (b) Minato, D.; Arimoto, H.;
Nagasue, Y.; Demizu, Y.; Onomura, O. Tetrahedron 2008, 64, 6675; Asymmetric
oxidation of aminoaldehydes: (c) Minato, D.; Nagasue, Y.; Demizu, Y.;
Onomura, O. Angew. Chem., Int. Ed. 2008, 47, 9458; Review: (d) Matsumura,
Y.; Onomura, O.; Demizu, Y. Yuki Gosei Kagaku Kyokaishi 2007, 65, 216.
8. Tosylation of DL-1a with chiral copper(II) catalyst gave the corresponding
tosylated product in 26% yield with 0% ee.
of BzCl improved the optical purity of the recovered
a-hydrox-
yalkanephosphonate (S)-3f (entry 7).
In conclusion, we have demonstrated a new nonenzymatic
method for kinetic resolution of -hydroxyalkanephosphonates.
a
The mechanistic study of this benzoylation and its further syn-
thetic applications are underway.
9. Kagan, H. B.; Fiaud, J. C.. In Topics in Stereochemistry; Eliel, E. L., Ed.; Wiley &
Sons: New York, 1988; Vol. 18, p 249.
10. The absolute stereoconfiguration of recovered (S)-1a was determined by
Acknowledgments
comparing with specific rotation of authentic sample. Compound (S)-1a: ½a D20
ꢁ
+11.7 (c 1.0, CHCl3, 79% ee). [lit.11 (S)-1a (91% ee); ½a 2D0
ꢁ
+21.9 (c 0.9, CHCl3)].
O.O. and Y.D. are very grateful to The Naito Foundation and a
Grant-in-Aid for Young Scientists (B) (19790017) from the Ministry
of Education, Science, Sports and Culture, Japan, respectively.
11. Yokomatsu, T.; Yoshida, Y.; Suemune, K.; Yamagishi, T.; Shibuya, S.
Tetrahedron: Asymmetry 1995, 6, 365.
12. Absolute stereoconfigurations of (R)-2b13 were determined by comparing with
specific rotation of authentic sample. Absolute stereoconfigurations of (R)-2c
and 2d shown in Table 1 were deduced on the basis of those of (R)-2a and 2b.
13. Rubio, M.; Suárez, A.; Álvarez, E.; Pizzano, A. Chem. Commun. 2005, 628.
References and notes
14.
A typical procedure for kinetic resolution of DL-1a: Under an aerobic
atmosphere, a solution of Cu(OTf)2 (9.0 mg, 0.025 mmol) and (R,R)-Ph-BOX
(8.4 mg, 0.025 mmol) in chlorobenzene (3 mL) was stirred for 10 min. Into the
solution were added DL-1a (129 mg, 0.5 mmol), BaCO3 (99 mg, 0.5 mmol), and
1. (a) Stowasser, B.; Budt, K. H.; Jian-Qi, L.; Peyman, A.; Ruppert, D. Tetrahedron
Lett. 1992, 33, 6625; (b) Sasai, H.; Bougauchi, M.; Arai, T.; Shibasaki, M.
Tetrahedron Lett. 1997, 38, 2717; (c) Zheng, X.; Nair, V. Tetrahedron 1999, 55,
BzCl (29 lL, 0.25 mmol) at 0 °C. The resulting mixture was allowed to stand