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Please login or sign up for a free trial to access the full content. Variation 3: Acetylide Anion Addition

DOI: 10.1055/sos-SD-029-00536

Ley, S. V.; Milroy, L.-G.; Myers, R. M.Science of Synthesis, (200729645.

Ring opening of lactones with acetylides provides direct access to hydroxy alk-1-ynyl ketones.[‌139‌‌155‌] The reaction of lactones 114 with lithium alkynyltrifluoroborates derived from alkynes of type 113 give alkynones 115, hydrogenation of which leads to the corresponding spiroketal products 116 (Scheme 34).[‌156‌] In this efficient approach, both alkyne and lactone starting materials are readily available and considerable structural variation is tolerated in both coupling partners. The use of the boron trifluoridediethyl ether complex to mediate the reactivity of the acetylides is essential to avoid double addition.

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