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3173 and refs. cited therein.
should be obtained in the absence of Ti(O-i-Pr)4. The detailed
mechanism is being pursued.
5 N. Ono, A. Kamimura and A. Kaji, Tetrahedron Lett., 1984, 25, 5319;
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These studies provide, to our knowledge, the first example of
organotitanium compounds combined with Ph3P mediated
reductive olefination giving trifluoromethylated trans-allylic
alcohols efficiently and stereoselectively. This ‘one-pot’ syn-
thesis is a very convenient starting point using commercially
available substances for the preparation of trifluoromethylated
allylic alcohols, and the widespread use of these allylic alcohols
is quite important in organic synthesis. They are interesting
fluorinated building blocks, not easily available by existing
synthetic methods.
Notes and References
† E-mail: shenyc@pub.sioc.ac.cn
‡ General experimental procedure: To a mixture of 3-bromo-1,1,1-tri-
fluoroacetone (1 mmol), aldehyde (1 mmol) and Ph3P (1 mmol) in a capped
vessel under nitrogen was injected Ti(O-i-Pr)4 (1 mmol). After stirring at
80 °C for 24 h, the reaction mixture was treated with 5% HCl (10 ml) and
extracted with Et2O (3 3 20 ml). The organic layer was washed with water
(3 3 10 ml), dried and evaporated to remove the solvent. The residue was
chromatographed on silica gel, and eluted with petroleum ether
(60–90 °C)–ethyl acetate (95:5) to give the product.
8 J. March, Advanced Organic Chemistry, 4th edn., John Wiley & Sons,
New York, 1992, p. 917.
9 R. K. Mackie, in Organophosphorus Reagents in Organic Synthesis, ed.
J. I. G. Cadogen, Academic Press, London, 1979, p.542.
10 Y. Shen and B. Yang, J. Organomet. Chem., 1989, 375, 45.
11 After fractional distillation under vacuum, a colorless oil 4 was obtained
which was sensitive to moisture. Bp 110 °C/0.1 torr; dH(300 MHz,
CDCl3, TMS) 5.00–4.20 (m, 4H), 3.58 [dd, 2J(H,H) 10.9, 3J(H,H) 3.2,
1H], 3.10 [dd, 2J(H,H) 10.6, 3J(H,H) 8.8, 1H], 1.28 [d, 3J(H,H) 6.1,
18H]; dF(60 MHz, CDCl3, TFA) 0.3 [d, 3J(H,F) 5.4].
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Received in Cambridge, UK, 10th August 1998; 8/06271D
2196
Chem. Commun., 1998