P. R. Likhar et al. / Tetrahedron Letters 43 (2002) 3333–3335
3335
(allyl)SnBu3, however, the reaction proceeds with the
same regioselectivity as depicted in Scheme 1.
of anhydrous ytterbium triflate (0.075 mmol, 15 mol%) in
dry and freshly distilled THF (4 ml). The stirring was
continued at the reaction temperature for the required
period of time (monitored by TLC). On completion, the
reaction mixture was diluted with water (5 ml) and the
aqueous layer was washed with dichloromethane (3×5
ml). The combined organic extract was dried over anhy-
drous sodium sulfate. Partial evaporation of the solvent
followed by separation on a silica gel column (1.5×7 cm,
60–120 mesh, petroleum ether/ethyl acetate 97/3 as elu-
ent) afforded analytically pure bishomoallyl alcohol as a
single isomer. The isolated yield was calculated based on
the amount of epoxide used and 98–99% mass balance
In summary, a simple, highly efficient method for the
preparation of bishomoallylic alcohols from aromatic
1,2-epoxides is presented, which utilizes Yb(OTf)3 to
achieve a totally regioselective ring opening.
Acknowledgements
The authors are grateful to the Department of Science
and Technology, New Delhi (Grant No.SP/S1/F11/97)
and the Director IICT for financial support (MLP-
2711). Valuable comments from the Referee are thank-
fully acknowledged.
1
was obtained. The products were characterized using H
NMR, IR and mass spectroscopy. Representative spec-
troscopic data for compound 2a (liquid): 1H NMR
(CDCl3) l: 2.05–2.35 (m, 2H), 2.70 (m, 2H), 3.75 (m,
1H), 5.01–5.1 (m, 2H), 5.80 (m, 1H), 7.1–7.3 (m, 5H); EI
1
MS m/z: 162. 2b (liquid): H NMR (CDCl3) l: 2.02–2.39
(m, 2H), 3.9 (d, 1H, J=9.4 Hz), 4.25–4.45 (m, 1H), 4.99
References
(s, 1H), 5.1 (d, 1H, J=7.1 Hz), 5.8–6.0 (m, 1H), 7.1–7.4
1
(m, 10H); EI MS m/z: 238. 2f (liquid): H NMR (CDCl3)
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