Heterocyclic Compounds
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ChemInform Abstract: Acetal-Initiated Cyclizations of Vinylsilanes. A General Synthesis of Allylically Unsaturated Oxacyclics.
First published: July 22, 1986
Abstract
Alkylation of the lithium reagent derived from the bromide (II) with the iodide (1) affords the (Z)-vinylsilane acetal (IIIa), which is cyclized to provide the tetrahydropyran (IVa).
ChemInform Abstract
Alkylation of the lithium reagent derived from the bromide (II) with the iodide (1) affords the (Z)-vinylsilane acetal (IIIa), which is cyclized to provide the tetrahydropyran (IVa). Isomerisation of (IIIa) gives the more stable (E)-vinylsilane (IIIb), which undergoes cyclization to give the tetrahydropyran (IVb). Avariety of similar Cyclizations is described, giving the oxacyclics (VI), (VIII) and (X). In contrast, cyclization of the (Z)-vinylsilane acetgg (XI) with TiCl4 gives the tetrahydropyran (XII).
