Unexpected products from the attempted organolithium-mediated conversion of β-methoxy aziridines into allylic amines

Article abstract of DOI:10.1016/j.tetlet.2009.11.059

The organolithium-mediated conversion of cyclic trans-β-methoxy aziridines and cis-β-methoxy aziridines with a tertiary alkoxy group adjacent to the aziridine into the corresponding substituted allylic sulfonamides is reported. In all cases, unexpected products were observed and the reactivity was completely different from other related cis-β-methoxy aziridines. The product distributions are highly dependent on the organolithium reagent employed and the structure of the methoxy aziridine Thus, together with our previous reports, the full scope and limitations of this approach to allylic sulfonamides are established.

Full text of DOI:10.1016/j.tetlet.2009.11.059

Tetrahedron Letters 51 (2010) 588–590
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Unexpected products from the attempted organolithium-mediated
conversion of b-methoxy aziridines into allylic amines
*
Susannah C. Coote, Peter O’Brien
Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
The organolithium-mediated conversion of cyclic trans-b-methoxy aziridines and cis-b-methoxy aziri-
dines with a tertiary alkoxy group adjacent to the aziridine into the corresponding substituted allylic sul-
fonamides is reported. In all cases, unexpected products were observed and the reactivity was completely
different from other related cis-b-methoxy aziridines. The product distributions are highly dependent on
the organolithium reagent employed and the structure of the methoxy aziridine Thus, together with our
previous reports, the full scope and limitations of this approach to allylic sulfonamides are established.
Ó 2009 Elsevier Ltd. All rights reserved.
Received 2 October 2009
Revised 27 October 2009
Accepted 13 November 2009
Available online 18 November 2009
Dedicated to Professor S. Florio on the
occasion of his 70th birthday.
In 1996, Mioskowski and co-workers reported the direct con-
version of cyclic b-methoxy epoxides into substituted allylic alco-
hols via reaction with organolithium reagents.1 This pioneering
contribution inspired us to develop the analogous reaction with
b-methoxy N-sulfonyl aziridines as a route to substituted allylic
sulfonamides. A generalized scheme for the process is summarized
in Scheme 1.2 Thus, treatment of aziridines cis-1 (n = 1 or 2) with
To start with, we investigated the reactions of b-methoxy aziridine
trans-5 with three different organolithium reagents (s-BuLi, Me3Si-
CH2Li and PhLi) (Scheme 2). The standard conditions involved
reacting the aziridine with 2.5 equiv of the organolithium reagent
in Et2O at À78 °C and then allowing the solution to warm up to
room temperature over 1 h before quenching with NH4Cl(aq). Using
s-BuLi and Me3SiCH2Li, none of the expected substituted allylic sul-
fonamides were produced. Instead, we isolated low yields (8–11%)
of allylic sulfonamide 98 (formed via b-elimination) together with
excess organolithium reagent (R2Li) gives
a-lithiated aziridines 2.
Then, carbenoid insertion of the
a-lithiated aziridines 2 into the
organolithium reagent (R2Li) gives 33 which can undergo methox-
ide elimination to ultimately form the products, allylic sulfona-
mides 4.
10–22% of TsNH2 (which is formed via a-lithiation, carbenoid
insertion into the organolithium reagent and elimination of TsNLi2
Our efforts have included examples of reactions of aziridines
derived from both cyclic2 and acyclic alkenes4 as well as the devel-
opment of methodology for the synthesis of azaspirocyclic natural
products.5,6 Our previous work with cyclic aziridines had utilized
aziridines cis-1 (R1 = H or alkyl) in reactions with a range of orga-
nolithium reagents. We had not reported any examples with
trans-stereochemistry since the cis diastereomers are more easily
prepared (aziridination of cyclic allylic alcohols gives the cis-hy-
droxy aziridines as the major or exclusive product7). Furthermore,
we had not explored aziridines in which there was a tertiary alkoxy
group adjacent to the aziridine. Thus, we decided to investigate the
organolithium-mediated transformation of aziridines trans-5,
trans-6, cis-7 and cis-8 (Fig. 1) into their corresponding substituted
allylic sulfonamides. Herein, we describe some unexpected find-
ings and hence fully map out the scope and limitations of this
methodology.
MeO
2
R
2
2.5 eq R Li, Et O
2
NTs
NHTs
1
( )
–78 °C, 5 min then
warm to rt over 1 h
n
( )
1
n
R
R
cis-1
4
n = 1 or 2
1 eq
2
R Li
Li
– MeOLi
2
MeO
MeO
1 eq
R
2
Li
R Li
NTs
( )
NLiTs
( )
n
n
1
R
2
3
Scheme 1.
MeO
n
Me
NTs
OMe
Bu
MeO
Aziridines trans-5, trans-6, cis-7 and cis-8 were prepared by
methylation (KHMDS, THF, À78 °C, Me2SO4 or MeI; Ag2O, MeI,
MeCN, reflux) of the corresponding known hydroxy aziridines.7
MeO
NTs
Me
NTs
trans-5
NTs
n
Bu
cis-7
cis-8
trans-6
* Corresponding author. Tel.: +44 1904 432535; fax: +44 1904 432516.
E-mail address: paob1@york.ac.uk (P. O’Brien).
Figure 1.
0040-4039/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2009.11.059

S. C. Coote, P. O’Brien / Tetrahedron Letters 51 (2010) 588–590
589
n
n
MeO
MeO
n
Bu
Bu
MeO
Bu
2.5 eq RLi, Et O
2
NHTs
MeO
MeO
Ph
2.5 eq PhLi
+
TsNH
NHTs
Me
2
NTs
trans-5
NTs
Me
+
–78 °C → rt
Et O
2
–78 °C → rt
NHTs
Me
9
cis-7
12 (61%)
13 (23%)
s
BuLi:
8%
11%
10%
22%
n
Me SiCH Li:
3
2
n
Bu
MeO
n
Bu
Bu
MeO
s
NHTs
2.5 eq BuLi
NHTs
MeO
NTs
Me
+
Ph
Et O
2
–78 °C → rt
2.5 eq PhLi, Et O
2
Me
Me
NTs
trans-5
–78 °C → rt
NHTs
10
cis-7
13 (67%)
14 (29%)
8%
n
n
n
Bu
MeO
MeO
Bu
Bu
Scheme 2.
MeO
n
NHTs
2.5 eq BuLi
NHTs
NTs
Me
+
Et O
2
–78 °C → rt
rather than methoxide). Although the yields were low, both these
types of reactivities are not seen with the diastereomeric b-meth-
oxy aziridine cis-5 (which gives 33% and 67% yields of substituted
allylic sulfonamides with s-BuLi and Me3SiCH2Li, respectively2).
With PhLi, the only product isolated was the substituted allylic sul-
fonamide 10 (8% yield) although it was formed in considerably
lower yield than b-methoxy aziridine cis-5 (58% yield).6 Disap-
pointingly, we could not improve the yields of these reactions
and we were unable to isolate the recovered starting material or
any other products.
Me
cis-7
13 (46%)
15 (27%)
n
BuLi
n
n
Bu
Bu
– MeOLi
MeO
NLiTs
Li
Li
β-elimination
NTs
Me
16
17
Scheme 4.
Next, the reactions between s-BuLi or PhLi and b-methoxy azi-
ridine trans-6 were explored but no allylic sulfonamides were
formed (Scheme 3). With s-BuLi, a 73% yield of TsNH2 was ob-
46% yield) (Scheme 4). However, different types of by-products
were also obtained from these reactions. Use of the more basic s-
BuLi led to allylic sulfonamide 1413 (29% yield), formed via a b-
elimination process analogous to that which gave 9 from aziridine
trans-5 (see Scheme 2). With n-BuLi, another new type of reactivity
was observed with the formation of diene sulfonamide 1514 (27%
yield). A speculative outline mechanism for the formation of 15
is shown in Scheme 4. Thus, b-elimination of the a-lithiated aziri-
dine intermediate 16 would lead to 17 which can undergo methox-
ide elimination to ultimately deliver 15 after work-up.
tained, which indicates
a-lithiation followed by reductive alkyl-
ation3 without methoxide elimination. To our surprise, the
reaction of PhLi with trans-6 gave sulfonamide 11 (50% yield), a re-
sult of aziridine ring-opening. The regio- and stereochemistry of
sulfonamide 11 are tentatively assigned based on 1H and 13C
NMR spectroscopy.9 In contrast, the diastereomeric b-methoxy azi-
ridine cis-6 was converted into the substituted allylic sulfonamides
in good yields (45% using s-BuLi;2 47% using PhLi6).
Finally, the reactions of b-methoxy aziridine cis-8 were ex-
plored. No substituted allylic sulfonamides were formed with n-
BuLi, s-BuLi or PhLi. Instead, mixtures of allylic sulfonamides 18
(formed by b-elimination) and enesulfonamide 19 (formed by
Thus, using b-methoxy aziridines trans-5 and trans-6 as repre-
sentative examples, we conclude that a cis-relationship between
the methoxy group and the aziridine is key to obtaining high yields
of substituted allylic sulfonamides via the route outlined in
Scheme 1.10 A similar difference in reactivity for diastereomeric
syn- and anti-methoxy aziridines derived from acyclic alkenes
has been noted previously.4
Our attention then turned to b-methoxy aziridines cis-7 and cis-
8 which contain a tertiary alkoxy substituent adjacent to the aziri-
dine together with cis-disposed methoxy and aziridine groups.
Encouragingly, the use of PhLi with cis-7 under the standard condi-
tions gave a 61% yield of the expected allylic sulfonamide 1211
(Scheme 4). This is comparable to the yield (66%) obtained by the
reaction of b-methoxy aziridine with a hydrogen in place of the
n-Bu group in cis-7.6 In addition, enesulfonamide 1312 (23% yield)
was isolated from the reaction and presumably forms via elimina-
elimination of the
a-lithiated aziridine) were isolated in 43–69%
yields (Scheme 5). Recrystallization of one of the mixtures of 18
and 19 gave pure enesulfonamide 19.15 In the lower yielding
examples, starting aziridine cis-8 was also recovered (20% using
n-BuLi; 30% using s-BuLi).
To conclude, the reaction of b-methoxy aziridines trans-5 and
trans-6 with organolithium reagents is not an efficient route to
substituted allylic sulfonamides. The best result was obtained
using PhLi and trans-5 which gave an 8% yield of 10. Instead, reac-
tions of the corresponding cis-b-methoxy aziridines should be uti-
lized as a route to the substituted allylic sulfonamides.2,5,6 In
addition, b-methoxy aziridines cis-7 and cis-8 which contain a ter-
tiary alkoxy group adjacent to the aziridine do not perform partic-
ularly well in their organolithium-mediated conversion into
substituted allylic sulfonamides. The expected mode of reactivity
was observed in only one case: reaction of aziridine cis-7 with PhLi
tion of the a-lithiated aziridine intermediate. Such a mode of reac-
tivity has been observed previously in cyclohexene-derived
tertiary-substituted b-methoxy aziridines5,6 but this is the first
example from a cyclopentene-derived aziridine.
The reactions of b-methoxy aziridine cis-7 with s-BuLi or n-BuLi
gave no substituted allylic sulfonamides and enesulfonamide 13
was the major product in each case (s-BuLi: 67% yield; n-BuLi:
Me
MeO
MeO
Me
NTs
MeO Me
NHTs
NHTs
2.5 eq RLi
+
Et O
2
–78 °C → rt
n
n
n
Bu
OMe
OMe
Bu
Bu
2.5 eq sBuLi
Et2O
78
73%
2.5 eq PhLi
Et2O
Ph
cis-8
18
19
TsNH2
NTs
65 : 35
65 : 35
25 : 75
(43%)
(58%)
(69%)
n-BuLi:
s-BuLi:
PhLi:
NHTs
°C rt
–
°C rt
–
78
50%
trans-6
11
Scheme 3.
Scheme 5.

590
S. C. Coote, P. O’Brien / Tetrahedron Letters 51 (2010) 588–590
11. Data for 12: colourless oil, Rf (4:1 hexane–EtOAc) 0.5; IR (film) 3265 (NH),
2956, 1452, 1325 (SO2), 1154 (SO2); 1H NMR (400 MHz, CDCl3) d 7.67 (d, J = 8.0,
2H, m-C6H4Me), 7.61 (d, J = 7.5, 1.0, 1H, Ph), 7.46 (t, J = 7.5, 2H, Ph), 7.39–7.10
(m, 4H, 4 Â CH), 4.58–4.54 (m, 1H, NH), 2.48–2.28 (m, 3H, 3 Â CH), 2.40 (s, 3H,
Me), 1.99–1.89 (m, 3H, 3 Â CH), 1.33 (app. quintet, J = 7.5, 2H, CH2), 1.28 (s, 3H,
Me), 1.21 (app. sextet, J = 7.5, 2H, CH2), 0.82 (t, J = 7.5, 3H, Me); 13C NMR
(100.6 MHz, CDCl3) d 143.9 (C), 142.7 (C), 140.7 (C), 140.3 (C), 135.5 (C), 129.6
(CH) 129.4 (CH), 128.1 (CH), 127.1 (CH), 126.8 (CH), 71.2 (CN), 37.9 (CH2), 32.3
(CH2), 30.0 (CH2), 29.1 (CH2), 25.3 (Me), 22.5 (CH2), 21.5 (Me), 13.9 (Me); MS
(ESI) m/z 406 [(M+Na)+, 35], 260 (40), 213 (100); HRMS (ESI) m/z: [M+Na]+
calcd for C23H29NO2S, 406.1822; found: 406.1807.
gave a 61% yield of allylic sulfonamide 12. Use of other organolith-
ium reagents and/or aziridine cis-8 led to a range of different types
of products: enesulfonamides 13 and 19, alternative allylic sulfon-
amides 14 and 18 and dienesulfonamide 15. Thus, with the results
from b-methoxy aziridines reported in this Letter together with
our previous reports,2,4–6 we have now fully mapped out the scope
and limitations of the organolithium-mediated conversion of
methoxy aziridines into substituted allylic sulfonamides.
12. Data for 13: colourless oil, Rf (4:1 hexane–EtOAc) 0.2; IR (film) 3252 (NH),
2931, 1460, 1383, 1323 (SO2), 1160 (SO2), 1092; 1H NMR (400 MHz, CDCl3) d
7.76 (d, J = 8.0, 2H, m-C6H4Me), 7.28 (d, J = 8.0, 2H, o-C6H4Me), 5.66 (br s, 1H,
NH), 2.95 (s, 3H, OMe), 2.41 (s, 3H, Me), 2.25–2.22 (m, 2H, 2 Â CH), 1.89–1.72
(m, 2H, 2 Â CH), 1.84 (s, 3H, Me), 1.19–0.94 (m, 5H, 5 Â CH), 0.82–0.77 (m, 1H,
CH), 0.77 (t, J = 7.0, 3H, Me); 13C NMR (100.6 MHz, CDCl3) d 143.4 (ipso-
C6H4SO2), 138.4 (C), 136.3 (C), 129.4 (m-C6H4Me), 128.3 (@C), 127.2 (o-
C6H4Me), 90.4 (CO), 49.7 (OMe), 37.5 (CH2), 33.9 (CH2), 27.5 (CH2), 25.5 (CH2),
23.0 (CH2), 21.5 (Me), 15.2 (Me), 13.9 (Me); MS (ESI) m/z 360 [(M+Na)+, 20],
344 (20), 338 (15), 328 (25), 322 (50), 306 (100); HRMS (ESI) m/z: [M+H]+ calcd
for C18H27NO3S, 338.1790; found: 338.1784.
13. Data for 14: colourless oil, Rf (99:1 CH2Cl2–acetone) 0.3; IR (film) 3306 (NH),
2933, 1587 (C@C), 1456, 1337 (SO2), 1161 (SO2), 1091; 1H NMR (400 MHz,
CDCl3) d 7.79 (d, J = 8.0, 2H, m-C6H4Me), 7.29 (d, J = 8.0, 2H, o-C6H4Me), 5.39 (br
d, J = 7.0, 1H, NH), 5.31 (app. quin, J = 1.5, 1H, @CH), 3.87 (br d, J = 7.0, 1H, CHN),
3.11 (s, 3H, OMe), 2.42 (s, 3H, Me), 2.40–2.35 (m, 1H, CH), 2.15–2.10 (m, 1H,
CH), 1.70 (br s, 3H, Me), 1.25–0.88 (m, 6H, 6 Â CH), 0.75 (t, J = 7.0, 3H, Me); 13C
NMR (100.6 MHz, CDCl3) d 143.1 (ipso-C6H4SO2), 139.9 (@C), 138.2 (ipso-
C6H4Me), 129.5 (m-C6H4Me), 127.4 (o-C6H4Me), 123.2 (@CH), 84.3 (CO), 65.2
(OMe), 51.0 (CHN), 37.3 (CH2), 35.1 (CH2), 26.2 (CH2), 23.0 (CH2), 21.5 (Me),
14.3 (Me), 13.8 (Me); MS (ESI) m/z 360 [(M+Na)+, 75], 338 (40), 306 (30), 167
(100); HRMS (ESI) m/z: [M+Na]+ calcd for C18H27NO3S, 360.1604; found:
360.1605.
14. Data for 15: colourless oil, Rf (9:1 hexane–EtOAc) 0.3; IR (film) 3259 (NH),
2956, 2928, 1383, 1327 (SO2), 1164 (SO2), 1093; 1H NMR (400 MHz, CDCl3) d
7.71 (d, J = 8.0, 2H, m-C6H4Me), 7.25 (d, J = 8.0, 2H, o-C6H4Me), 5.50 (br s, 1H,
NH), 4.47 (br s, 1H, @CHAHB), 4.37 (t, J = 2.5, 1H, @CHAHB), 2.49–2.36 (m, 4H,
4 Â CH), 2.42 (s, 3H, Me), 2.16–2.13 (m, 2H, 2 Â CH), 1.32–1.19 (m, 4H, 4 Â CH),
0.87 (t, J = 7.5, 3H, Me); 13C NMR (100.6 MHz, CDCl3) d 151.6 (@C), 150.3 (@C),
143.5 (ipso-C6H4SO2), 137.5 (ipso-C6H4Me), 130.7 (@C), 129.4 (m-C6H4Me),
127.3 (o-C6H4Me), 99.2 (@CH2), 30.7 (CH2), 29.4 (CH2), 28.8 (CH2), 27.3 (CH2),
22.8 (CH2), 21.5 (Me), 13.9 (Me); MS (ESI) m/z 328 [(M+Na)+, 40], 322 (35), 306
(100); HRMS (ESI) m/z: [M + H]+ calcd for C17H23NO2S, 306.1522; found:
306.1519.
15. Data for 19: white solid, Rf (1:1 hexane–Et2O) 0.2; IR (Nujol mull) 3377 (NH),
1341 (SO2), 1160 (SO2), 1092; 1H NMR (400 MHz, CDCl3) d 7.79 (d, J = 8.0, 2H,
m-C6H4Me), 7.29 (d, J = 8.0, 2H, o-C6H4Me), 5.93 (s, 1H, NH), 3.08 (s, 3H, OMe),
2.40 (s, 3H, Me), 2.08–2.00 (m, 3H, 3 Â CH), 1.90–1.62 (m, 3H, 3 Â CH), 1.54–
1.48 (m, 1H, CH), 1.32–1.18 (m, 3H, 3 Â CH), 1.24 (s, 3H, Me), 1.05–0.89 (m, 2H,
2 Â CH), 0.74 (t, J = 7.5, 3H, Me); 13C NMR (100.6 MHz, CDCl3) d 142.9 (ipso-
C6H4SO2), 139.4 (C), 137.5 (C), 129.2 (m-C6H4Me), 128.4 (@C), 126.7 (o-
C6H4Me), 77.2 (CO), 49.3 (OMe), 33.4 (CH2), 32.5 (CH2), 30.9 (Me), 29.4 (CH2),
29.1 (CH2), 24.2 (Me), 22.5 (CH2), 21.5 (Me), 19.5 (CH2), 13.8 (Me); MS (ESI) m/z
374 [(M+Na)+, 100], 358 (20), 318 (20), 226 (20), 181 (50), 165 (40); HRMS
(ESI) m/z: [M+Na]+ calcd for C19H29NO3S, 374.1941; found: 374.1932.
Diagnostic signals for 18: 1H NMR (400 MHz, CDCl3) 5.47–5.44 (m, 1H, @CH),
4.89 (d, J = 9.0, 1H, NH), 3.88 (br d, J = 9.0, 1H, CHN), 3.12 (s, 3H, OMe), 2.41 (s,
3H, Me), 1.18 (s, 3H, Me), 0.77 (t, J = 7.5, 3H, Me).
Acknowledgment
We thank the EPSRC for a DTA award (to S.C.C).
References and notes
1. Dechoux, L.; Doris, E.; Mioskowski, C. Chem. Commun. 1996, 549.
2. Rosser, C. M.; Coote, S. C.; Kirby, J. P.; O’Brien, P.; Caine, D. Org. Lett. 2004, 6,
4817.
3. (a) O’Brien, P.; Rosser, C. M.; Caine, D. Tetrahedron Lett. 2003, 44, 6613; (b)
O’Brien, P.; Rosser, C. M.; Caine, D. Tetrahedron 2003, 59, 9779.
4. Moore, S. P.; O’Brien, P.; Whitwood, A. C.; Gilday, J. Synlett 2008, 237.
5. Moore, S. P.; Coote, S. C.; O’Brien, P.; Gilday, J. Org. Lett. 2006, 8, 5145.
6. Coote, S. C.; Moore, S. P.; O’Brien, P.; Whitwood, A. C.; Gilday, J. J. Org. Chem.
2008, 73, 7852.
7. Coote, S. C.; O’Brien, P.; Whitwood, A. C. Org. Biomol. Chem. 2008, 6, 4299.
8. Data for 9: colourless oil, Rf (1:1 petrol–Et2O) 0.1; IR (Nujol mull) 3269 (NH),
1329 (SO2), 1161 (SO2), 1095; 1H NMR (400 MHz, CDCl3) d 7.80 (d, J = 8.0, 2H,
m-C6H4Me), 7.33 (d, J = 8.0, 2H, o-C6H4Me), 5.84–5.81 (m, 1H,@CH), 5.34–5.31
(m, 1H, @CH), 4.47 (d, J = 9.0, 1H, NH), 4.30–4.26 (m, 1H, CHN), 3.78 (d, J = 7.0,
3.0, 1H, CHO), 3.29 (s, 3H, OMe), 2.70–2.62 (m, 1H, CH), 2.45 (s, 3H, Me), 2.26–
2.20 (m, 1H, CH); 13C NMR (100.6 MHz, CDCl3) d 143.5 (ipso-C6H4SO2), 137.7
(ipso-C6H4Me), 133.7 (@CH), 129.7, 128.3 (@CH), 127.2, 86.6 (CHO), 64.6 (CHN),
57.1 (OMe), 37.4 (CH2), 21.5 (Me); MS (CI, NH3) m/z 285 [(M+NH4)+, 100], 268
(45); HRMS (CI, NH3) m/z: [M+NH4]+ calcd for C13H17NO3S, 285.1267; found:
285.1268.
9. Data for 11: white solid, mp 176–178ꢀC, Rf (1:1 petrol–Et2O) 0.2; IR (Nujol mull)
3249 (NH), 1326 (SO2), 1156 (SO2), 1082; 1H NMR (400 MHz, CDCl3) d 7.44 (d,
J = 8.0, 2H, m-C6H4Me), 7.21 (d, J = 8.0, 2H, o-C6H4Me), 7.16 (t, J = 7.5, 1.5, 1H,
Ph), 7.05 (t, J = 7.5, 2H, Ph), 6.92 (d, J = 7.5, 1.5, 2H, Ph), 4.06 (d, J = 4.5, 1H, NH),
3.64 (t, J = 11.5, 4.5, 1H, CHN), 3.40 (br s, 1H, CHO), 3.02 (s, 3H, OMe), 2.48–2.44
(m, 2H, 2 Â CH), 2.46 (s, 3H, Me), 2.05–1.99 (m, 1H, CH), 1.70 (app. qd, J = 13.5,
3.5, 1H, CH), 1.57–1.52 (m, 1H, CH), 1.41–1.26 (m, 2H, 2 Â CH); 13C NMR
(100.6 MHz, CDCl3) d 142.9 (ipso-C6H4SO2), 139.1 (ipso-C6H4Me), 136.9 (ipso-
Ph), 129.4, 129.0, 128.2, 127.2, 126.8, 80.0 (CHO), 56.8 (OMe), 54.1 (CH), 51.8
(CH), 34.7 (CH2), 28.1 (CH2), 21.5 (Me), 18.7 (CH2); MS (CI, NH3) m/z 377
[(M+NH4)+, 40], 360 (100); HRMS (CI, NH3) m/z: [M+H]+ calcd for C20H25NO3S,
360.1628; found: 360.1626.
10. In Mioskowski’s original report (see Ref. 1), there was one example of the
conversion of a trans-b-methoxy epoxide into a substituted allylic alcohol
(>95% yield):
n
n
Bu
Bu
MeO
n
Bu
n
2.5 eq BuLi, THF
O
OH
–78 °C → rt
Me
Me
trans
>95%