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DOI: 10.1055/sos-SD-036-00485

Hodgson, D. M.; Humphreys, P. G.Science of Synthesis, (200836650.

Although the treatment of an allylic alcohol with acid appears to be a straightforward route to structural isomers, secondary reactions typically hamper the efficiency of this approach. Such secondary reactions may lead to other geometrical stereoisomers as well as to skeletal rearrangements.[‌15‌] Nevertheless, there are examples of certain biased substrates that undergo allylic rearrangement provided one isomer is substantially more stable than the others, such as when isomerization brings a nonconjugated alkene into conjugation. In such cases near quantitative yields can be obtained.[‌358‌] However, in less biased systems, such as that present in the ene-diyne 164, a mixture of products is isolated. Thus, even though the desired E-allylic alcohol 165 is formed in 56% yield, the other isomers 166 and 167 are also generated in a combined yield of 26% (Scheme 77).[‌359‌]

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