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9. General procedure: Method A. A 2.0 M solution of
ethylmagnesium chloride (excess) in THF was added
dropwise over 30 min at room temperature to a solution
of ester 4 (1 mmol) and a titanium reagent (1.1 mmol) in
THF (6 mL). After the mixture had been stirred for 30
min, it was quenched by addition of water. The product
5 was isolated by normal workup processing and purified
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was added dropwise over 30 min at room temperature to
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mixture had been stirred for 30 min, it was quenched by
addition of water. The products 8 and 9 were isolated by
normal workup processing and purified by silica gel
chromatography.
10. In Method B, use of titanium tetraisopropoxide and
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respectively, in the absence of ethyl acetate.
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