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Configurational stability of allenic anions, use of a vitamin D derived CD fragment as a stereochemical probe and the stereoselective synthesis of precursors

✍ Scribed by Eugène M.G.A. van Kruchten; Alberto Haces; William H. Okamura

Book ID: 104221551
Publisher: Elsevier Science
Year: 1983
Tongue: French
Weight: 292 KB
Volume: 24
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(00)88230-1

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✦ Synopsis

Metallation (n-BuLi, t-BuOK, THF) followed by quenching (DCl, occurs primarily with retention-of configuration, D20) of (S)-allenes 4a_c whereas that of CR)-allenes 4d-e occurs mainly with inversion; the allenes 4_were prepared from related propargyl alcohols (k??9). a-Recently, in connection with vitamin D studies, we made the unusual observation that metallation (tert-butyllithium, ether, -78 to -55 "C) of 1 followed by quenching of the resultant allenyllithium species with a suitable electrophile affords 2_and 3in ratios as high as 13.5 to

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