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Synlett 1995; 1995(9): 978-980
DOI: 10.1055/s-1995-5115
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Chelation-Directed Asymmetric Lithiation and C-Substitution of 1,2,4-Butanetriol Acetonide

Hendrik Helmke, Dieter Hoppe*
  • *Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, D-48149 Münster, Germany
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Publikationsdatum:
31. Dezember 2000 (online)

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The 4-O-(2,2,4,4-tetramethyl-1,3-oxazolidine-3-carboxylate) 1 of (S)-1,2-O-isopropylidene-1,2,4-butanetriol is readily deprotonated by sec-butyllithium in ether with high lk-diastereoselectivity: The presumed bicyclic chelate complex 2⋅OEt 2 is trapped by various electrophiles to form optically active adducts 4 with > 95% diastereoselectivity, serving as a synthetic equivalent for the unknown (1S,3S)-1,3,4-trihydroxybutanide ion. External complexation of tertiary diamines can compete with the internal oxygen ligand, leading to modified stereoselectivities.

carbamate esters - diastereoselective lithiation - enantioenriched 1,2,4-alkanetriols - chiral 1-oxyalkyllithium

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