Asymmetric [2,3] Sigmatropic Rearrangement of Chiral Allylic Selenonium Ylides

Full text of DOI:10.1021/jo962384a

4562
J . Org. Chem. 1997, 62, 4562-4563
Sch em e 1
Asym m etr ic [2,3] Sigm a tr op ic
Rea r r a n gem en t of Ch ir a l Allylic
Selen on iu m Ylid es
Noriyuki Kurose, Tamiko Takahashi, and
Toru Koizumi*
Faculty of Pharmaceutical Sciences, Toyama
Medical & Pharmaceutical University,
2630 Sugitani, Toyama 930-01, J apan
Received December 20, 1996
Quite recently, we reported that the nucleophilic
substitution reaction of the chloroselenuranes 1 having
allylic substituents with amides gave the chiral allylic
amines 3 with up to 93% enantiomeric excess (ee)
(Scheme 1).1 The result indicates that the nucleophilic
substitution reaction of 1 with amides selectively pro-
ceeds with retention of configuration to generate the
chiral allylic selenimides 2 in situ, which undergo the
[2,3] sigmatropic rearrangement highly selectively when
the substituent (R′) on nitrogen is sufficiently bulky. If
the nucleophilic substitution reaction of 1 with carbon
nucleophiles generated chiral selenonium ylides 4, and
the [2,3] sigmatropic rearrangement of 4 proceeded
stereoselectively, this rearrangement would be a new
method for carbon-carbon bond formation with chiral
induction at the C(3) stereocenter. We have already
reported that the nucleophilic substitution reaction of the
chloroselenurane with active methylene compounds as
a carbon nucleophile proceeds in a highly stereoselective
manner with retention of configuration to give sele-
nonium ylides.2 Little is known about the stereochemisty
of the [2,3] sigmatropic rearrangement of the selenonium
ylide, and to the best of our knowledge, there has been
only one example of the asymmetric [2,3] sigmatropic
rearrangement using a chiral allylic selenonium ylide by
Uemura and co-workers.3 In this case, both the chemical
yield and the selectivity of the rearrangement were low.
We report here the first successful example of the
asymmetric [2,3] sigmatropic rearrangement of the chiral
allylic selenonium ylides 4 generated by the nucleophilic
substitution reaction of the chloroselenuranes 1 with
(phenylsulfonyl)acetonitrile.
Ta ble 1. Asym m etr ic [2,3] Sigm a tr op ic Rea r r a n gem en t
of Ch ir a l Selen on iu m Ylid es
entry
R
time (h)
product
yield (%)
1
2
3
4
5
Bn
0.5
1
1
1
0.5
5a
5b
5c
5d
5e
78
87
83
85
30
Meb
n-Pr
n-Hex
Ph
a
b
Isolated yield of the major isomer. E:Z ) 83:17.
Sch em e 2a
We examined the [2,3] sigmatropic rearrangement of
the allylic selenonium ylides as follows. To the solution
of 1a -e in CH2Cl2 were added Et3N (1 equiv) and
(phenylsulfonyl)acetonitrile (1 equiv) at -20 °C. Reaction
time and isolated yield of 5a -e are shown in Table 1.
When 1a was used, we obtained homoallylic selenide 5a
in 78% isolated yield along with its minor diastereomers4
and diastereomeric deselenenyl compounds 6a (entry 1).
In the same manner, treatment of 1b-e with (phenyl-
sulfonyl)acetonitrile gave 5b-e (30-87% yield) as a
single diastereomer (entries 2-5).5 These results indi-
cate that the [2,3] sigmatropic rearrangement of the
a
Key: (a) Na(Hg), Na2HPO4, MeOH, 88% (from 3a D); (b) Zn,
HCl, THF, then NaCl, H2O, DMSO, 160 °C, 88% (from 3a B); (c)
HCl, MeOH, 75% (from 3a D and 3a B); (d) RuCl3, NaIO4, H2O-
CH3CN-CCl4, then CH2N2, 82%; (e) 1 N NaOH, MeOH, 73%.
resulting allylic selenonium ylides 4 proceeds in a highly
stereoselective manner to yield homoallylic selenides 5.
In order to determine the absolute configuration of the
allylic C(3) position of the diastereomer 5a , we converted
5a into 2-benzylbutanedioic acid 10 (Scheme 2). The
product mixture from 1a was treated with 5% Na(Hg)6
to give 7 (88% yield from 1a ). Methanolysis of 7 afforded
8 (76% yield and 88% ee). The ee of 8 was determined
by HPLC using a Daicel Chiralcel OJ column (hexane/
i-PrOH ) 95/5). Reaction of 8 with RuCl3‚nH2O and
(1) Kurose, N.; Takahashi, T.; Koizumi, T. J . Org. Chem. 1996, 61,
2932.
(2) Takahashi, T.; Kurose, N.; Kawanami, S.; Nojiri, A.; Arai, Y.;
Koizumi, T.; Shiro, M. Chem. Lett. 1995, 379.
(3) Nishibayashi, Y.; Ohe, K.; Uemura, S. J . Chem. Soc., Chem.
Commun. 1995, 1245.
(4) When 1a was used, we obtained homoallylic selenides(ca. 92:5:
2:1, 5a ; 78% isolated yield)4 and diastereomeric deselenenyl compounds
6a (4% yield). The structures and the diastereomers ratio were
determined by 1H NMR spectrum.
(5) Minor products of 5b-e and 6b-d could not be detected by 1H
NMR spectra. In the case of entry 5, diastereomeric deselenyl
compounds 6e were isolated in 31% yield.
(6) Trost, B. M.; Arndt, H. C.; Strege, P. E.; Verhoeven, T. R.
Tetrahedron Lett. 1976, 39, 3477.
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Communications
J . Org. Chem., Vol. 62, No. 14, 1997 4563
Sch em e 3
the two endo transition states, the transition state 11 is
much more favorable than the transition state 11′
because the steric interaction between R and PhSO2
groups across the developing C(2′)-C(3) bond should be
increased in the case of 11′.10 Therefore, the [2,3]
sigmatropic rearrangement of the allylic selenonium
ylides 4 should selectively progress via the endo transi-
tion state 11 to give homoallylic selenides 5.
In conclusion, the [2,3] sigmatropic rearrangement of
the allylic selenonium ylides 4 (1) affords the homoallylic
selenides 5 with high diastereoselectivity and in high
chemical yield and (2) provides an excellent method for
carbon-carbon bond formation with chiral induction at
C(3) stereocenter.
We are now investigating synthetic studies on the
asymmetric [2,3] sigmatropic rearrangement of the allylic
selenonium ylides 4.
Ack n ow led gm en t. This work was supported by the
Proposal-Based Advanced Industrial Technology R & D
Program of the New Energy and Industrial Technology
Development Organization (NEDO) of J apan (T.K.), by
Grants-in-Aid for Scientific Research from the Ministry
of Education, Science, Sports and Culture, J apan, No.
07214214 (T.K.), No. 07457519 (T.K.), and No. 07672261
(T.T.), by Hoan Sha Foundation (T.K.), by The Tamura
Foundation for Promotion of Science and Technology
(T.T.), and by the Sasakawa Scientific Research Grant
from The J apan Science Society (N.K).
7
NaIO4 followed by treatment with CH2N2 gave (R)-
dimethyl 2-benzylbutanedioate 9 (80% yield in two steps).
Hydrolysis of (R)-9 yielded (R)-2-benzylbutanedioic acid
10 [[R]25D +24.5° (c 1.18, AcOEt) (R-form: lit.8 [R]25D +27°
(c 1.5, AcOEt))] (76% yield). Accordingly, the absolute
configuration at the allylic C(3) position of the diastere-
omer 5a was determined to be S.
On the basis of these results, we propose the stereo-
chemical course of the asymmetric [2,3] sigmatropic
rearrangement of the allylic selenonium ylides shown in
Scheme 3.9 In this rearrangement, the endo transition
states 11 and 11′ should be more stable than the exo
transition states 12 and 12′ to yield the homoallyl
compound 5a having C(3)-(S) absolute configuration. Of
Su p p or tin g In for m a tion Ava ila ble: Experimental pro-
cedures, characterization data, and 1H and 13C NMR spectra
for new compounds (7 pages).
J O962384A
(7) Carlsen, P. H. J .; Katsuki, T.; Martin, V. S.; Sharpless, B. J .
Org. Chem. 1981, 46, 3936.
(8) Cohen, S. G.; Milovanovic, A. J . Am. Chem. Soc. 1968, 90, 3495.
(9) Mechanisms of [2,3] sigmatropic rearrangement of allylic sulfo-
nium ylides have been studied in detail: Wu, Y. D.; Houk, K. N. J .
Org. Chem. 1991, 56, 5657 and references cited therein.
(10) For the [2,3] sigmatropic rearrangement of allylic sulfonium
ylide: Hartley, R. C.; Richards, I. C.; Warren, S. J . Chem. Soc., Perkin
Trans. 1 1996, 359.