938
LETTERS
SYNLETT
vinyl-stabilized 2-lithio-1,3-dithianes with 1,2-disubstituted
epoxides, see: (b) Amrein, W.; Schaffner, K. Helv. Chim. Acta
1975, 58, 380-397. (c) Bennasar, M.-L.; Torrens, A.; Rubiralta,
M.; Bosch, J.; Grierson, D. S.; Husson, H.-P. Heterocycles 1989,
29, 745-760. (d) Rubiralta, M.; Diez, A.; Reig, I.; Castells, J.;
Bettiol, J.-L.; Grierson, D. S.; Husson, H.-P. Heterocycles 1990,
31, 173-186.
(12) The compound 11 was prepared from 2,2-dimethyl-1,3-
propanediol by the following four steps: (1) TrCl, NaH, THF, rt, 3
h; (2) Swern oxid.; (3) 1,3-propanedithiol, BF OEt , CH Cl , 0
3•
2
2
2
°C, 0.5 h, then CSA, MeOH, rt, 1 h; (4) TBDPSCl, imidazole,
DMF, rt, 3 h, 49% for four steps.
(13) The racemic 13 was prepared from glycidol via silylation
(TBDPSCl, imidazole, CH Cl , rt, 1 h, 88%), 1,3-dithiane
2
2
addition (1,3-dithiane, n-BuLi, THF, -30 °C, 1 h) and silylation
(TBDPSCl, DMAP, DMF, 100 °C, 36 h, 89% for two steps).
(5) The chiral compounds 6 and 9 were prepared from methyl (S)-3-
hydroxy-2-methylpropionate by the following five steps: (1) TrCl,
(14) (a) Yasuda, M.; Ide, M.; Matsumoto, Y.; Nakata, M. Synlett 1997,
899-902. (b) Yasuda, M.; Ide, M.; Matsumoto, Y.; Nakata, M.
Bull. Chem. Soc. Jpn. in press.
Et N, DMAP, CH Cl , rt, 24 h; (2) LiAlH , THF, 0 °C, 2 h; (3)
3
2
2
4
Swern oxid.; (4) 1,3-propanedithiol, BF OEt , CH Cl , -30 °C,
3•
2
2
2
0.5 h, then CSA, MeOH, rt, 1 h; (5) to 6: TBDPSCl, imidazole,
DMF, rt, 0.5 h, 58% for five steps. to 9: TBSCl, imidazole, DMF,
0 °C, 0.5 h, 55% for five steps. The enantiomer of 6 was prepared
by Smith et al., see ref 3h.
(15) (a) Kodama, M.; Matsuki, Y.; Ito, S. Tetrahedron Lett. 1975, 3065-
3068. (b) Biellmann, J.-F.; Ducep, J.-B. Org. React. 1982, 27, 1-
344.
(16) 2-Metallo-1,3-dithiane derivatives other than lithium, see:
(a) Kruse, C. G.; Wijsman, A.; van der Gen, A. J. Org. Chem.
1979, 44, 1847-1851. (b) Weidmann, B.; Widler, L.; Olivero, A.
G.; Maycock, C. D.; Seebach, D. Helv. Chim. Acta 1981, 64, 357-
361. (c) Carre, M. C.; Ndebeka, G.; Riondel, A.; Bourgasser, P.;
Caubere, P. Tetrahedron Lett. 1984, 25, 1551-1554. (d) Jones, A.
B.; Villalobos, A.; Linde, R. G., II; Danishefsky, S. J. J. Org.
Chem. 1990, 55, 2786-2797. (e) Cer_, V.; Angelis, S. D.;
Pollicino, S.; Ricci, A.; Reddy, C. K.; Knochel, P.; Cahiez, G.
Synthesis, 1997, 1174-1178. See also refs 8g and 9.
(6) Satisfactory analytical data (NMR spectra and elemental analyses)
were obtained for all new compounds.
(7) The racemic 7 was prepared from (E)-2-buten-1-ol via tritylation
(TrCl, Et N, CH Cl , rt, 2 h, 61%) and epoxidation (m-CPBA,
3
2
2
CH Cl , rt, 3 h, 74%).
2
2
(8) For examples of lithiation of 2-substituted-1,3-dithiane derivatives
by n-BuLi or t-BuLi in the presence of HMPA, see: (a) Sum, P.-E.;
Weiler, L. Can. J. Chem. 1978, 56, 2700-2702. (b) Brown, C. A.;
Yamaichi, A. J. Chem. Soc., Chem. Commun. 1979, 100-101.
(c) Sum, P.-E.; Weiler, L. Can. J. Chem. 1982, 60, 327-334.
(d) Williams, D. R.; Sit, S.-Y. J. Am. Chem. Soc. 1984, 106, 2949-
2954. (e) Lipshutz, B. H.; Kotsuki, H.; Lew, W. Tetrahedron Lett.
1986, 27, 4825-4828. (f) Davey, A. E.; Taylor, R. J. K. J. Chem.
Soc., Chem. Commun. 1987, 25-27. (g) Solladie, G.; Hutt, J.
Tetrahedron Lett. 1987, 28, 797-800. (h) Toshima, H.; Suzuki, T.;
Nishiyama, S.; Yamamura, S. Tetrahedron Lett. 1989, 30, 6725-
6728. (i) Khandekar, G.; Robinson, G. C.; Stacey, N. A.; Thomas,
E. J.; Vather, S. J. Chem. Soc., Perkin Trans. 1, 1993, 1507-1519.
(j) Ohmori, K.; Suzuki, T.; Miyazawa, K.; Nishiyama, S.;
Yamamura, S. Tetrahedron Lett. 1993, 34, 4981-4984. (k) Reich,
H. J.; Borst, J. P.; Dykstra, R. R. Tetrahedron 1994, 50, 5869-
5880. See also refs 3b, 3c, 3d, 3f, 3g, 3h, and 3i.
(17) BuLi/Bu Mg complex has been used, as
a catalyst, for
2
polymerization of monomers. For example, see: Kamienski, C.
W.; Gastonia, N. C.; Eastham, J. F. U. S. Patent 3847883 (1974);
Chem. Abstr. 82, 58590 (1975). The same complex has been used
for metallation of substituted trifluoromethylbenzenes, see:
Castaldi, G.; Borsotti, G. European Patent 0491326A2; Chem.
Abstr. 117, 150667 (1992).
(18) The structrue elucidation of diorganomagnesium-organolithium
complexes, see: (a) Seitz, L. M.; Brown, T. L. J. Am. Chem. Soc.
1966, 88, 4140-4147. (b) Seitz, L. M.; Little, B. F. J.
Organometal. Chem. 1969, 18, 227-241. (c) Malpass, D. B.;
Eastham, J. F. J. Org. Chem. 1973, 38, 3718-3723. (d) Ashby, E.
C.; Chao, L.-C.; Laemmle, J. J. Org. Chem. 1974, 39, 3258-3263.
(e) Greiser, T.; Kopf, J.; Thoennes, D.; Weiss, E. Chem. Ber. 1981,
114, 209-213. (f) Richey, H. G., Jr.; Farkas, J., Jr. Organometallics
1990, 9, 1778-1784.
(9) Lipshutz, B. H.; Garcia, E. Tetrahedron Lett. 1990, 31, 7261-7264.
(10) Each compound of 8 and 10 is a 1:1 mixture of diastereomers. The
compound 14 is a 1.9:1 mixture of diastereomers. In the structures
of 8, 10, 12, and 14, Me and OH substituents originated from 7 are
arranged to syn.
(11) Besides them, the compound i was produced as a by-product
derived from epoxide 7 in less than 5% yield.
Figure 1
Addendum
The Editorial Office would like to apologise for unnecessary changes in text made to the letter by Heaney, H.; Simcox, M.; Slawin, A.; Giles, R.
Synlett 1998, 640 during the editorial process.