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44.2.1.2.6 Variation 6: Ring-Opening Reactions

DOI: 10.1055/sos-SD-044-00109

Ohno, H.; Tomioka, K.Science of Synthesis, (200844111.

The ring-opening reduction of cyclic ethers is also a useful procedure for the synthesis of allenes. Thus, treatment of 2-alkynyloxiranes 223 and 225 with lithium aluminum hydride provides allenic triols 224 and 226, respectively, both in a stereospecific manner (Scheme 68).[‌114‌,‌115‌] In these reactions, the involvement of a cyclic aluminum intermediate 227 explains the observed syn displacement of the departing oxygen atom by a hydride.

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References


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