Science of Synthesis

Marsden, S. P., Science of Synthesis, (2005) 26, 1097.

As outlined in Section ‌26.9.1.1.15‌, vinylogous esters such as ‌299‌ and ‌302‌ undergo kinetic deprotonation at the α′-site, providing access to α′-substituted enones ‌300‌ and ‌303‌. In conjunction with the chemistry discussed in Section ‌26.9.1.1.7.2‌, whereby nucleophilic 1,2-addition to the vinylogous ester is followed by acid-mediated rearrangement to the transposed enone, this constitutes a two-step approach to the synthesis of γ-alkylated enones. Suitable nucleophiles included hydride sources such as lithium aluminum hydride, leading to monofunctionalized ketones, e.g. ‌301‌ (‌Scheme 52‌).[‌237‌] Alternatively, the addition of hard carbon nucleophiles such as organolithiums yields more highly substituted enones (e.g., ‌304‌) on rearrangement.[‌238‌]

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References